Fix bug where CanaryWeight is reset to 0 during CanaryPhasePromoting

[sayap]

This is just a display issue in the status, that can cause some confusion.

[codecov-commenter]

Codecov Report

:white_check_mark: All modified and coverable lines are covered by tests. :white_check_mark: Project coverage is 29.87%. Comparing base (12ee6cb) to head (095a31d). :warning: Report is 67 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1851      +/-   ##
==========================================
- Coverage   39.44%   29.87%   -9.58%     
==========================================
  Files         287      287              
  Lines       22706    18422    -4284     
==========================================
- Hits         8956     5503    -3453     
+ Misses      12777    12189     -588     
+ Partials      973      730     -243     

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