fix: Make retry policy back off more aggressively for RPCs that retry RESOURCE_EXHAUSTD (#979)

* fix: Make retry policy back off more aggressively for RPCs that retry RESOURCE_EXHAUSTD

PiperOrigin-RevId: 557935020

Source-Link: googleapis/googleapis@38e1f31

Source-Link: googleapis/googleapis-gen@5bbe39d
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* 🦉 Updates from OwlBot post-processor

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

---------

Co-authored-by: Owl Bot 

Author: gcf-owl-bot[bot]

samples/generated_samples/snippet_metadata_google.pubsub.v1.json

@@ -8,7 +8,7 @@
     ],
     "language": "PYTHON",
     "name": "google-cloud-pubsub",
-    "version": "2.18.2"
+    "version": "0.1.0"
   },
   "snippets": [
     {