QtcProcess: Get rid of setProcessUserEventWhileRunning()

Introduce EventLoopMode enum and pass it to the
QtcProcess::runBlocking() instead. There is no need to
store this setting. By default this value is NoEventLoop.

Change-Id: Icad98b77bec5280b79039b7e5aa4ec408261521c
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: hjk <hjk@qt.io>
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>

src/plugins/perforce/perforceplugin.cpp

@@ -1270,8 +1270,7 @@ PerforceResponse PerforcePluginPrivate::synchronousProcess(const FilePath &worki
     }
     process.setTimeOutMessageBoxEnabled(true);
     process.setCommand({m_settings.p4BinaryPath.filePath(), args});
-    process.setProcessUserEventWhileRunning();
-    process.runBlocking();
+    process.runBlocking(QtcProcess::WithEventLoop);
 
     PerforceResponse response;
     response.error = true;