[receiver/awscontainerinsight] Fix memory leak on shutdown in k8s API server

[crobert-1]

Description:

This change has 4 main parts:

1. Shutdown the k8s API server's broadcaster during Shutdown as it has its own running goroutines that need shutdown to avoid leaking.
2. Call Shutdown in the failure scenarios of New. This is required because once again, goroutines are started during the k8s API server's New call stack. Since it returns nil on error, there's no way to shutdown once it returns. This means Shutdown must be called on error.
3. Only set the server's broadcaster after passed in options are complete. This will help avoid a goroutine leak as well, as explained in the added comment in the code.
4. Add goleak checks to help ensure no goroutines are being leaked.

Link to tracking Issue:
#30438

Testing:
All existing tests are passing, as well as added goleak checks.

[crobert-1]

Failures are frequencies of #32391 and #32396, I've added references on both issues.

[github-actions]

This PR was marked stale due to lack of activity. It will be closed in 14 days.

[fatsheep9146]

nicely ping @Aneurysm9 for review

[github-actions]

This PR was marked stale due to lack of activity. It will be closed in 14 days.