Fix multi proxy race condition (#909)

Refactored PR of #904 for easier review.  Once #908 is reviewed & merged, this will be easier to review.

src/api-service/__app__/onefuzzlib/proxy.py

@@ -169,6 +169,9 @@ class Proxy(ORMMixin):
         self.delete()
 
     def is_outdated(self) -> bool:
+        if self.state not in VmState.available():
+            return True
+
         if self.version != __version__:
             logging.info(
                 PROXY_LOG_PREFIX + "mismatch version: proxy:%s service:%s state:%s",