Automatic merge from submit-queue (batch tested with PRs 41248, 41214)
Switch hpa controller to shared informer
**What this PR does / why we need it**: switch the hpa controller to use a shared informer
**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes #
**Special notes for your reviewer**: Only the last commit is relevant. The others are from #40759, #41114, #41148
**Release note**:
```release-note
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cc @smarterclayton @deads2k @sttts @liggitt @DirectXMan12 @timothysc @kubernetes/sig-scalability-pr-reviews @jszczepkowski @mwielgus @piosz