refactor: Remove useless CBlock::GetBlockHeader

diff --git a/src/merkleblock.cpp b/src/merkleblock.cpp
index 34ff06e5..f5aaddba 100644
--- a/src/merkleblock.cpp
+++ b/src/merkleblock.cpp
@@ -29,7 +29,7 @@ std::vector<bool> BytesToBits(const std::vector<unsigned char>& bytes)
 
 CMerkleBlock::CMerkleBlock(const CBlock& block, CBloomFilter* filter, const std::set<Txid>* txids)
 {
-    header = block.GetBlockHeader();
+    header = static_cast<const CBlockHeader&>(block);
 
     std::vector<bool> vMatch;
     std::vector<Txid> vHashes;
diff --git a/src/net_processing.cpp b/src/net_processing.cpp
index 5fd11d3c..3a712f2f 100644
--- a/src/net_processing.cpp
+++ b/src/net_processing.cpp
@@ -4666,7 +4666,7 @@ void PeerManagerImpl::ProcessMessage(CNode& pfrom, const std::string& msg_type,
             mapBlockSource.emplace(hash, std::make_pair(pfrom.GetId(), true));
 
             // Check claimed work on this block against our anti-dos thresholds.
-            if (prev_block && prev_block->nChainWork + GetBlockProof(pblock->GetBlockHeader()) >= GetAntiDoSWorkThreshold()) {
+            if (prev_block && prev_block->nChainWork + GetBlockProof(*pblock) >= GetAntiDoSWorkThreshold()) {
                 min_pow_checked = true;
             }
         }
diff --git a/src/primitives/block.h b/src/primitives/block.h
index 207d2b29..afaeba0d 100644
--- a/src/primitives/block.h
+++ b/src/primitives/block.h
@@ -101,18 +101,6 @@ public:
         m_checked_merkle_root = false;
     }
 
-    CBlockHeader GetBlockHeader() const
-    {
-        CBlockHeader block;
-        block.nVersion       = nVersion;
-        block.hashPrevBlock  = hashPrevBlock;
-        block.hashMerkleRoot = hashMerkleRoot;
-        block.nTime          = nTime;
-        block.nBits          = nBits;
-        block.nNonce         = nNonce;
-        return block;
-    }
-
     std::string ToString() const;
 };
 
diff --git a/src/test/blockfilter_index_tests.cpp b/src/test/blockfilter_index_tests.cpp
index 224acb8b..4a3f4d42 100644
--- a/src/test/blockfilter_index_tests.cpp
+++ b/src/test/blockfilter_index_tests.cpp
@@ -102,10 +102,9 @@ bool BuildChainTestingSetup::BuildChain(const CBlockIndex* pindex,
     chain.resize(length);
     for (auto& block : chain) {
         block = std::make_shared<CBlock>(CreateBlock(pindex, no_txns, coinbase_script_pub_key));
-        CBlockHeader header = block->GetBlockHeader();
 
         BlockValidationState state;
-        if (!Assert(m_node.chainman)->ProcessNewBlockHeaders({{header}}, true, state, &pindex)) {
+        if (!Assert(m_node.chainman)->ProcessNewBlockHeaders({{*block}}, true, state, &pindex)) {
             return false;
         }
     }
diff --git a/src/test/fuzz/block_header.cpp b/src/test/fuzz/block_header.cpp
index 2e446b16..12a9e1a2 100644
--- a/src/test/fuzz/block_header.cpp
+++ b/src/test/fuzz/block_header.cpp
@@ -33,10 +33,10 @@ FUZZ_TARGET(block_header)
         mut_block_header.SetNull();
         assert(mut_block_header.IsNull());
         CBlock block{*block_header};
-        assert(block.GetBlockHeader().GetHash() == block_header->GetHash());
+        assert(block.GetHash() == block_header->GetHash());
         (void)block.ToString();
         block.SetNull();
-        assert(block.GetBlockHeader().GetHash() == mut_block_header.GetHash());
+        assert(block.GetHash() == mut_block_header.GetHash());
     }
     {
         std::optional<CBlockLocator> block_locator = ConsumeDeserializable<CBlockLocator>(fuzzed_data_provider);
diff --git a/src/test/fuzz/utxo_snapshot.cpp b/src/test/fuzz/utxo_snapshot.cpp
index 56d36155..35faa73a 100644
--- a/src/test/fuzz/utxo_snapshot.cpp
+++ b/src/test/fuzz/utxo_snapshot.cpp
@@ -89,7 +89,7 @@ void initialize_chain()
         auto& chainman{*setup->m_node.chainman};
         for (const auto& block : chain) {
             BlockValidationState dummy;
-            bool processed{chainman.ProcessNewBlockHeaders({{block->GetBlockHeader()}}, true, dummy)};
+            bool processed{chainman.ProcessNewBlockHeaders({{*block}}, true, dummy)};
             Assert(processed);
             const auto* index{WITH_LOCK(::cs_main, return chainman.m_blockman.LookupBlockIndex(block->GetHash()))};
             Assert(index);
@@ -171,7 +171,7 @@ void utxo_snapshot_fuzz(FuzzBufferType buffer)
         if constexpr (!INVALID) {
             for (const auto& block : *g_chain) {
                 BlockValidationState dummy;
-                bool processed{chainman.ProcessNewBlockHeaders({{block->GetBlockHeader()}}, true, dummy)};
+                bool processed{chainman.ProcessNewBlockHeaders({{*block}}, true, dummy)};
                 Assert(processed);
                 const auto* index{WITH_LOCK(::cs_main, return chainman.m_blockman.LookupBlockIndex(block->GetHash()))};
                 Assert(index);
diff --git a/src/test/validation_block_tests.cpp b/src/test/validation_block_tests.cpp
index a0b23f5d..6497a243 100644
--- a/src/test/validation_block_tests.cpp
+++ b/src/test/validation_block_tests.cpp
@@ -104,7 +104,7 @@ std::shared_ptr<CBlock> MinerTestingSetup::FinalizeBlock(std::shared_ptr<CBlock>
     // submit block header, so that miner can get the block height from the
     // global state and the node has the topology of the chain
     BlockValidationState ignored;
-    BOOST_CHECK(Assert(m_node.chainman)->ProcessNewBlockHeaders({{pblock->GetBlockHeader()}}, true, ignored));
+    BOOST_CHECK(Assert(m_node.chainman)->ProcessNewBlockHeaders({{*pblock}}, true, ignored));
 
     return pblock;
 }