[SHOT-251] build: update Dockerfile to use Ubuntu 22.04

[mimartin12]

🎟️ Tracking

https://bitwarden.atlassian.net/browse/SHOT-251

📔 Objective

Cherry-pick

[github-actions]

🤖 Bitwarden Claude Code Review

Overall Assessment: APPROVE

This PR is a one-line cherry-pick into rc that changes the MsSql utility image base from mcr.microsoft.com/mssql/server:2025-CU5-ubuntu-24.04 to the ubuntu-22.04 variant of the same SQL Server 2025 CU5 release. The SQL Server version is unchanged, so the mssql-conf and mssql-tools18 paths used later in the Dockerfile remain valid, and the gosu/tzdata apt packages are available on Jammy. No other file in the repo pins the MsSql utility image, so nothing else needs to move with it. The change matches commit e1a9b96fb already merged to main (#8183), so rc and main stay aligned.

Code Review Details

No findings.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 63.13%. Comparing base (16a41c2) to head (87ae05e).
⚠️ Report is 1 commits behind head on rc.

Additional details and impacted files

@@            Coverage Diff             @@
##               rc    #8195      +/-   ##
==========================================
- Coverage   67.79%   63.13%   -4.67%     
==========================================
  Files        2337     2344       +7     
  Lines      101456   101864     +408     
  Branches     9167     9247      +80     
==========================================
- Hits        68787    64312    -4475     
- Misses      30362    35341    +4979     
+ Partials     2307     2211      -96     

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