fix(ci): pass Codecov token to C# and Java test jobs

[hubcio]

Coverage uploads from these jobs silently failed because
the reusable _test.yml workflow received no token. Only
the Rust job had the secrets block, so Codecov never
posted PR comments for C# or Java changes.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 68.40%. Comparing base (66a9c7c) to head (60c0c2e).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #2800      +/-   ##
============================================
- Coverage     68.41%   68.40%   -0.02%     
  Complexity      656      656              
============================================
  Files           852      852              
  Lines         68182    68182              
  Branches      59643    59653      +10     
============================================
- Hits          46645    46638       -7     
+ Misses        19205    19201       -4     
- Partials       2332     2343      +11     

Flag	Coverage Δ
csharp	67.06% <ø> (-0.19%)	⬇️
java	52.19% <ø> (ø)
rust	69.58% <ø> (+<0.01%)	⬆️

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see 15 files with indirect coverage changes

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