- fix global variable access

src/utils_qualtest.py

@@ -58,6 +58,7 @@ TRACE_TOTAL_TIMEOUT = 30
 # a webpage is mostly I/O bound, it's not going to be significant.
 
 def trace_function(frame, event, arg):
+    global TRACE_START_TIME
     if time.time() - TRACE_START_TIME > TRACE_TOTAL_TIMEOUT:
         raise Exception('Timed out!') # Use whatever exception you consider appropriate.
 
@@ -114,6 +115,7 @@ class QualtestBackend:
         
 
     def upload_audio(self, probe_id, path_recorded: Path):
+        global TRACE_START_TIME
         result = False
 
         # Log about upload attempt