fix: remove ambiguous error codes from query retries (googleapis#2308)

Context: internal issue b/445984807 comment 10.

Author: tswast

google/cloud/bigquery/retry.py

@@ -121,9 +121,6 @@ def _should_retry_get_job_conflict(exc):
 """
 
 job_retry_reasons = (
-    "rateLimitExceeded",
-    "backendError",
-    "internalError",
     "jobBackendError",
     "jobInternalError",
     "jobRateLimitExceeded",