citra_qt: Write to config file on important config changes (#6311)

Qt isn't always writing changes on save. This causes config to be lost on crash. This PR ensures all changes are always saved on the file.

Ported from yuzu.

Co-authored-by: Narr the Reg <5944268+german77@users.noreply.github.com>

src/citra_qt/configuration/config.cpp

@@ -821,6 +821,7 @@ void Config::SaveValues() {
     SaveLayoutValues();
     SaveAudioValues();
     SaveSystemValues();
+    qt_config->sync();
 }
 
 void Config::SaveAudioValues() {