Merge #19378: refactor: Use Mutex type for g_cs_recent_confirmed_transactions

1307686 refactor: Use Mutex type for g_cs_recent_confirmed_transactions (Hennadii Stepanov)

Pull request description:

  No need the `RecursiveMutex` type for the `g_cs_recent_confirmed_transactions`.

  Related to #19303.

ACKs for top commit:
  MarcoFalke:
    ACK 1307686
  vasild:
    ACK 1307686

Tree-SHA512: 67f1be10c80ec18d0f80b9f5036e5a20986314da9b9364ef4e193ad1d9f3f4c8e4c2e16253ca79d649ff602d5b8c2aff58d7dd1085841afb760479a4875cffbe

Author: MarcoFalke

src/net_processing.cpp

@@ -189,7 +189,7 @@ namespace {
      * We use this to avoid requesting transactions that have already been
      * confirnmed.
      */
-    RecursiveMutex g_cs_recent_confirmed_transactions;
+    Mutex g_cs_recent_confirmed_transactions;
     std::unique_ptr<CRollingBloomFilter> g_recent_confirmed_transactions GUARDED_BY(g_cs_recent_confirmed_transactions);
 
     /** Blocks that are in flight, and that are in the queue to be downloaded. */