Use fmt::runtime in FmtFormatT

This format string is by definition dynamic and can't be checked at compile time.  There are other similar strings in the log handler and in asserts, but they use vformat and thus don't need fmt::runtime.  We might be able to do a similar thing where the untranslated string is compile-time checked, but FmtFormatT is used in so few places that I don't want to handle that in this PR.

Source/Core/Common/MsgHandler.h

@@ -73,7 +73,7 @@ void SetAbortOnPanicAlert(bool should_abort);
 template <typename... Args>
 std::string FmtFormatT(const char* string, Args&&... args)
 {
-  return fmt::format(Common::GetStringT(string), std::forward<Args>(args)...);
+  return fmt::format(fmt::runtime(Common::GetStringT(string)), std::forward<Args>(args)...);
 }
 }  // namespace Common