Increase timeout limit for test case

This test seems to be intermittently failing on CI with a timeout, but
despite the frequency of failure, there doesn't seem to be any
fundamental reason for it to fail and it works locally %100 of
time. So trying to increase the timeout limit to see if all it needs
is more time.

Author: cderici

tests/integration/test_model.py

@@ -623,7 +623,7 @@ async def test_local_oci_image_resource_charm(event_loop):
             lambda: (
                 len(charm.units) > 0 and
                 charm.units[0].workload_status in terminal_statuses),
-            timeout=60 * 4,
+            timeout=60 * 10,
         )
         assert charm.units[0].workload_status == 'active'