Add third party annotation support for maintenance job

[Lyndon-Li]

Add third party annotation support for maintenance job, so that the declared third party annotations could be added to the maintenance job pods.

Otherwise, there is the same problem for maintenance jobs as #8754 for data movers.

[codecov]

Codecov Report

Attention: Patch coverage is 38.46154% with 8 lines in your changes missing coverage. Please review.

Project coverage is 59.56%. Comparing base (883e3e4) to head (f1dcb7b).
Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
pkg/util/velero/velero.go	0.00%	5 Missing ⚠️
pkg/repository/maintenance/maintenance.go	62.50%	2 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #8812      +/-   ##
==========================================
- Coverage   59.57%   59.56%   -0.01%     
==========================================
  Files         370      370              
  Lines       40228    40239      +11     
==========================================
+ Hits        23966    23969       +3     
- Misses      14764    14771       +7     
- Partials     1498     1499       +1     

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[kaovilai]

The current list of "well known annotations" only include aws.

velero/pkg/util/third_party.go

Lines 23 to 25 in 883e3e4

	var ThirdPartyAnnotations = []string{
	"iam.amazonaws.com/role",
	}

Do we need to add more to really address #8811?

[Lyndon-Li]

We don't need it as far as I understand.
The problem happens just because the maintenance pod has inherited some labels/annotations from Velero server pod. While in a previous PR, we have changed the code not to inherit any labels/annotations from it, so the problem should have been fixed.