Fix compile errors when building snap package

* System icons are no longer used eliminating the need to differentiate behavior for the snap package on Linux.

src/core/Bootstrap.cpp

@@ -85,12 +85,6 @@ namespace Bootstrap
         bootstrap();
         MessageBox::initializeButtonDefs();
 
-#ifdef KEEPASSXC_DIST_SNAP
-        // snap: force fallback theme to avoid using system theme (gtk integration)
-        // with missing actions just like on Windows and macOS
-        QIcon::setThemeSearchPaths(QStringList() << ":/icons");
-#endif
-
 #ifdef Q_OS_MACOS
         // Don't show menu icons on OSX
         QApplication::setAttribute(Qt::AA_DontShowIconsInMenus);