logger: show message popup for log_fatal (#412)

## Link to GitHub Issue, if one exists
#410 

## Description of change
When raising fatal errors via `log_fatal`, also show a modal popup.

Update instances of `log_fatal` where the message was too long to fit.

## Testing
Tested various failure conditions.

src/spice2x/util/deferlog.h

@@ -11,5 +11,4 @@ namespace deferredlogs {
 
     void defer_error_messages(std::initializer_list<std::string> messages);
     void dump_to_logger(bool is_crash=false);
-    void show_popup_for_crash();
 }