fix: perserve peerDependencies, peerDependenciesMeta in transition mode

[JoshuaKGoldberg]

PR Checklist

• Addresses an existing open issue: fixes 🐛 Bug: package.json removes existing peerDependencies, peerDependenciesMeta #2059
• That issue was marked as status: accepting prs
• Steps in CONTRIBUTING.md were taken

Overview

Expands the options.packageData schema to allow them. These are the first allowlisted package.json properties that aren't manually combined with addons, so they're generally spread in blockPackageJson.

🎁

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.81%. Comparing base (91824c6) to head (9f2f4bb).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2061   +/-   ##
=======================================
  Coverage   99.81%   99.81%           
=======================================
  Files         120      120           
  Lines        4996     4999    +3     
  Branches      313      313           
=======================================
+ Hits         4987     4990    +3     
  Misses          9        9           

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[github-actions]

🎉 This is included in version v2.18.1 🎉

The release is available on:

• GitHub releases
• npm package (@latest dist-tag)

Cheers! 📦🚀