Cherry-pick #45300: Updated color levels for dashboard charts to match Figma

[lukeheath]

Cherry-pick of #45300 into the RC branch.

[claude]

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 54.95%. Comparing base (9de8af6) to head (3787001).
⚠️ Report is 38 commits behind head on rc-minor-fleet-v4.85.0.

Additional details and impacted files

@@                     Coverage Diff                     @@
##           rc-minor-fleet-v4.85.0   #45307       +/-   ##
===========================================================
- Coverage                   66.72%   54.95%   -11.77%     
===========================================================
  Files                        2626     1016     -1610     
  Lines                      211198    26365   -184833     
  Branches                     9428     9180      -248     
===========================================================
- Hits                       140924    14490   -126434     
+ Misses                      57485    11817    -45668     
+ Partials                    12789       58    -12731     

Flag	Coverage Δ
android	?
backend	?
backend-activity	?
fleetd-chrome	?
frontend	54.95% <ø> (+0.21%)	⬆️

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