[config/configretry] Migrate BackOffConfig to schema-based configuration generated by mdatagen

[jkoronaAtCisco]

Description

Migrate config/configretry to mdatagen schema-based configuration. Removes the hand-written BackOffConfig struct and NewDefaultBackOffConfig constructor in favor of generated code driven by metadata.yaml and config.schema.json.

Authorship

• I, a human, wrote this pull request description myself.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.05%. Comparing base (0dff746) to head (4178c53).

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #15502   +/-   ##
=======================================
  Coverage   91.05%   91.05%           
=======================================
  Files         729      730    +1     
  Lines       48478    48485    +7     
=======================================
+ Hits        44143    44150    +7     
  Misses       3008     3008           
  Partials     1327     1327           

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[github-actions]

This PR was marked stale due to lack of activity. It will be closed in 14 days.

[codspeed-hq]

Merging this PR will not alter performance

⚠️ Unknown Walltime execution environment detected

Using the Walltime instrument on standard Hosted Runners will lead to inconsistent data.

For the most accurate results, we recommend using CodSpeed Macro Runners: bare-metal machines fine-tuned for performance measurement consistency.

✅ 3 untouched benchmarks
🗄️ 2 archived benchmarks run¹

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_{Comparing jkoronaAtCisco:migrate_configretry (4178c53) with main (0dff746)}

Footnotes

1. 2 benchmarks were run, but are now archived. If they were deleted in another branch, consider rebasing to remove them from the report. Instead if they were added back, click here to restore them. ↩