Increase memory limits for Flux notification controller

General MR

Summary

From dogfood the lower limits were causing consistent OOM crashes. Doubling the memory limits makes everything work.

I believe this change is required as a result of https://repo1.dso.mil/platform-one/big-bang/bigbang/-/merge_requests/1896 - with the increased actions from the notification controller it requires more memory (especially on a large cluster with all packages deployed).