use pointer for podstatistics and resourceusage

[DanielXLee]

What type of PR is this?

What this PR does / why we need it:

introduced by #362

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

[dixudx]

Nice fix.

[codecov-commenter]

Codecov Report

Merging #421 (932e83c) into main (33de040) will increase coverage by 0.00%.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main     #421   +/-   ##
=======================================
  Coverage   13.68%   13.69%           
=======================================
  Files          60       60           
  Lines        6578     6574    -4     
=======================================
  Hits          900      900           
+ Misses       5612     5608    -4     
  Partials       66       66           

Impacted Files	Coverage Δ
...clusters/clusterstatus/clusterstatus_controller.go	5.40% <0.00%> (+0.09%)	⬆️

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