Fix memory leak found by copilot

Co-authored-by: softins <softins@users.noreply.github.com>
See: #3702

Author: ann0see

src/clientdlg.cpp

@@ -876,9 +876,7 @@ void CClientDlg::OnChatTextReceived ( QString strChatText )
 {
     if ( pSettings->bEnableAudioAlerts )
     {
-        QSoundEffect* sf = new QSoundEffect();
-        sf->setSource ( QUrl::fromLocalFile ( ":sounds/res/sounds/new_message.wav" ) );
-        sf->play();
+        PlayAudioAlert ( QUrl::fromLocalFile ( ":sounds/res/sounds/new_message.wav" ) );
     }
     ChatDlg.AddChatText ( strChatText );
 
@@ -927,9 +925,7 @@ void CClientDlg::OnNumClientsChanged ( int iNewNumClients )
 {
     if ( pSettings->bEnableAudioAlerts && iNewNumClients > iClients )
     {
-        QSoundEffect* sf = new QSoundEffect();
-        sf->setSource ( QUrl::fromLocalFile ( ":sounds/res/sounds/new_user.wav" ) );
-        sf->play();
+        PlayAudioAlert ( QUrl::fromLocalFile ( ":sounds/res/sounds/new_user.wav" ) );
     }
 
     // iNewNumClients will be zero on the first trigger of this signal handler when connecting to a new server.

src/clientdlg.h

@@ -60,7 +60,6 @@
 #include <QMessageBox>
 #include <QFileDialog>
 #include <QActionGroup>
-#include <QSoundEffect>
 #if QT_VERSION >= QT_VERSION_CHECK( 5, 6, 0 )
 #    include <QVersionNumber>
 #endif

src/util.cpp

@@ -1679,3 +1679,16 @@ QString TruncateString ( QString str, int position )
     }
     return str.left ( position );
 }
+
+void PlayAudioAlert ( QUrl soundUrl )
+{
+    QSoundEffect* sf = new QSoundEffect();
+    QObject::connect ( sf, &QSoundEffect::playingChanged, sf, [sf]() {
+        if ( !sf->isPlaying() )
+        {
+            sf->deleteLater();
+        }
+    } );
+    sf->setSource ( soundUrl );
+    sf->play();
+}

src/util.h

@@ -75,6 +75,8 @@
 #include <QElapsedTimer>
 #include <QTextBoundaryFinder>
 #include <QTimer>
+#include <QSoundEffect>
+
 #ifndef DISABLE_SRV_DNS
 #    include <QDnsLookup>
 #endif
@@ -1407,3 +1409,5 @@ struct EnumClassHash
     }
 };
 #endif
+
+void PlayAudioAlert ( QUrl soundUrl );