feat: reclaim space in release pipeline

[jukie]

Adds reclaim-storage step to v1.4 release worklow. Relates to #7587 and fixes failing pipeline here - https://github.com/envoyproxy/gateway/actions/runs/19566911461

[shawnh2]

Thanks

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 71.23%. Comparing base (b8dbca2) to head (04da70a).
⚠️ Report is 1 commits behind head on release/v1.4.

Additional details and impacted files

@@               Coverage Diff                @@
##           release/v1.4    #7613      +/-   ##
================================================
- Coverage         71.29%   71.23%   -0.06%     
================================================
  Files               217      217              
  Lines             29461    29461              
================================================
- Hits              21003    20988      -15     
- Misses             6919     6934      +15     
  Partials           1539     1539              

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