removed duplicate calling of GetDescriptorScriptPubKeyMan

Removed duplicate call to GetDescriptorScriptPubKeyMan and
Instead of checking linearly I have used find method so time complexity reduced significantly for GetDescriptorScriptPubKeyMan
after this fix improved performance of importdescriptor part refs #32013.

src/wallet/test/fuzz/scriptpubkeyman.cpp

@@ -80,8 +80,12 @@ static std::optional<std::pair<WalletDescriptor, FlatSigningProvider>> CreateWal
 static DescriptorScriptPubKeyMan* CreateDescriptor(WalletDescriptor& wallet_desc, FlatSigningProvider& keys, CWallet& keystore)
 {
     LOCK(keystore.cs_wallet);
-    keystore.AddWalletDescriptor(wallet_desc, keys, /*label=*/"", /*internal=*/false);
-    return keystore.GetDescriptorScriptPubKeyMan(wallet_desc);
+    DescriptorScriptPubKeyMan* descriptor_spk_manager = nullptr;
+    auto spk_manager = *Assert(keystore.AddWalletDescriptor(wallet_desc, keys, /*label=*/"", /*internal=*/false));
+    if (spk_manager) {
+        descriptor_spk_manager = dynamic_cast<DescriptorScriptPubKeyMan*>(spk_manager);
+    }
+    return descriptor_spk_manager;
 };
 
 FUZZ_TARGET(scriptpubkeyman, .init = initialize_spkm)

src/wallet/test/psbt_wallet_tests.cpp

@@ -27,7 +27,8 @@ static void import_descriptor(CWallet& wallet, const std::string& descriptor)
     assert(descs.size() == 1);
     auto& desc = descs.at(0);
     WalletDescriptor w_desc(std::move(desc), 0, 0, 10, 0);
-    wallet.AddWalletDescriptor(w_desc, provider, "", false);
+    auto spk_manager = *Assert(wallet.AddWalletDescriptor(w_desc, provider, "", false));
+    assert(spk_manager);
 }
 
 BOOST_AUTO_TEST_CASE(psbt_updater_test)

src/wallet/test/util.cpp

@@ -35,7 +35,8 @@ std::unique_ptr<CWallet> CreateSyncedWallet(interfaces::Chain& chain, CChain& cc
         assert(descs.size() == 1);
         auto& desc = descs.at(0);
         WalletDescriptor w_desc(std::move(desc), 0, 0, 1, 1);
-        if (!wallet->AddWalletDescriptor(w_desc, provider, "", false)) assert(false);
+        auto spk_manager = *Assert(wallet->AddWalletDescriptor(w_desc, provider, "", false));
+        assert(spk_manager);
     }
     WalletRescanReserver reserver(*wallet);
     reserver.reserve();
@@ -209,7 +210,7 @@ wallet::ScriptPubKeyMan* CreateDescriptor(CWallet& keystore, const std::string&
     WalletDescriptor w_desc(std::move(desc), timestamp, range_start, range_end, next_index);
 
     LOCK(keystore.cs_wallet);
-
-    return Assert(keystore.AddWalletDescriptor(w_desc, keys,/*label=*/"", /*internal=*/false));
+    auto spkm = Assert(keystore.AddWalletDescriptor(w_desc, keys,/*label=*/"", /*internal=*/false));
+    return spkm.value();
 };
 } // namespace wallet

src/wallet/test/wallet_tests.cpp

@@ -69,7 +69,8 @@ static void AddKey(CWallet& wallet, const CKey& key)
     assert(descs.size() == 1);
     auto& desc = descs.at(0);
     WalletDescriptor w_desc(std::move(desc), 0, 0, 1, 1);
-    if (!wallet.AddWalletDescriptor(w_desc, provider, "", false)) assert(false);
+    auto spk_manager = *Assert(wallet.AddWalletDescriptor(w_desc, provider, "", false));
+    assert(spk_manager);
 }
 
 BOOST_FIXTURE_TEST_CASE(scan_for_wallet_transactions, TestChain100Setup)