fix eviction manager getEvictPodFromCandidates sort order

[luomingmeng]

What type of PR is this?

Bug fixes

What this PR does / why we need it:

Which issue(s) this PR fixes:

Special notes for your reviewer:

[codecov]

Codecov Report

Attention: Patch coverage is 71.42857% with 2 lines in your changes missing coverage. Please review.

Project coverage is 56.82%. Comparing base (bbf3ec5) to head (d7db1e8).
Report is 5 commits behind head on main.

Files with missing lines	Patch %	Lines
pkg/agent/evictionmanager/manager.go	71.42%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #756      +/-   ##
==========================================
+ Coverage   56.79%   56.82%   +0.03%     
==========================================
  Files         601      601              
  Lines       69839    69845       +6     
==========================================
+ Hits        39662    39688      +26     
+ Misses      25918    25893      -25     
- Partials     4259     4264       +5     

Flag	Coverage Δ
unittest	56.82% <71.42%> (+0.03%)	⬆️

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