Merge bitcoin/bitcoin#23644: wallet: Replace confusing getAdjustedTime() with GetTime()

fa37e798b2 wallet: Replace confusing getAdjustedTime() with GetTime() (MarcoFalke)

Pull request description:

  Setting `nTimeReceived` to the adjusted time has several issues:

  * `m_best_block_time` is set to the "unadjusted" time, thus a comparison of the two times is like comparing apples to oranges. In the worst case this opens up an attack vector where remote peers can force a premature re-broadcast of wallet txs.
  * The RPC documentation for `"timereceived"` doesn't mention that the network adjusted time is used, possibly confusing users when the time reported by RPC is off by a few seconds compared to their local timestamp.

  Fix all issues by replacing the call with `GetTime()`. Also a style fix: Use non-narrowing integer conversion in the RPC method.

ACKs for top commit:
  theStack:
    Code-review ACK fa37e798b2
  shaavan:
    crACK fa37e798b2

Tree-SHA512: 8d020ba400521246b7aed4b6c41319fc70552e8c69e929a5994500375466a9edac02a0ae64b803dbc6695df22276489561a23bd6e030c44c97d288f7b9b2b3fa

src/node/interfaces.cpp

@@ -656,7 +656,6 @@ public:
         return chainman().ActiveChainstate().IsInitialBlockDownload();
     }
     bool shutdownRequested() override { return ShutdownRequested(); }
-    int64_t getAdjustedTime() override { return GetAdjustedTime(); }
     void initMessage(const std::string& message) override { ::uiInterface.InitMessage(message); }
     void initWarning(const bilingual_str& message) override { InitWarning(message); }
     void initError(const bilingual_str& message) override { InitError(message); }