Fix package plugin tests flakes

[shyaamsn]

What this PR does / why we need it

Fix couple of issues in package plugin:

1. In slow testbeds applying registry server fails. Hence added retries
2. kapp-controller PackageInstall reverts the changes to the kapp-controller configmap in workload cluster. Hence pausing the PackageInstall.

Which issue(s) this PR fixes

Fixes #3097

Describe testing done for PR

Ran package plugin integration tests and they pass

Release note

Fix package plugin tests flakiness

Additional information

Special notes for your reviewer

[github-actions]

Cluster Generation A/B Results:
https://storage.googleapis.com/tkg-clustergen/3096/20220806060439/clustergen.diff.txt
Author/reviewers:
Please review to verify that the effects on the generated cluster configurations are exactly what the PR intended, and give a thumbs-up if so.

[github-actions]

Cluster Generation A/B Results:
https://storage.googleapis.com/tkg-clustergen/3096/20220806165311/clustergen.diff.txt
Author/reviewers:
Please review to verify that the effects on the generated cluster configurations are exactly what the PR intended, and give a thumbs-up if so.

[codecov]

Codecov Report

Merging #3096 (1daffe5) into main (ac3165c) will increase coverage by 0.06%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main    #3096      +/-   ##
==========================================
+ Coverage   44.40%   44.47%   +0.06%     
==========================================
  Files         417      417              
  Lines       42320    42320              
==========================================
+ Hits        18791    18820      +29     
+ Misses      21798    21776      -22     
+ Partials     1731     1724       -7     

Impacted Files	Coverage Δ
...ons/controllers/packageinstallstatus_controller.go	79.15% <0.00%> (+1.15%)	⬆️
addons/controllers/clusterbootstrap_controller.go	65.57% <0.00%> (+2.29%)	⬆️

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[shivaani0505]

LGTM