fix: platform add with tarball

[erisu]

Platforms affected

n/a

Motivation and Context

Fix installing platforms with tarball.

cordova platform add cordova platform add ../cordova-android-12.0.0.tgz will append @latest to the end and causes install failures.

Description

Only append @latest to only platforms that are known.

Testing

npm t

Checklist

• [ ] I've run the tests to see all new and existing tests pass
• [ ] I added automated test coverage as appropriate for this change
• [ ] Commit is prefixed with (platform) if this change only applies to one platform (e.g. (android))
• [ ] If this Pull Request resolves an issue, I linked to the issue in the text above (and used the correct keyword to close issues using keywords)
• [ ] I've updated the documentation if necessary

[codecov-commenter]

Codecov Report

Merging #918 (ee558de) into master (1979863) will decrease coverage by 0.02%. The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #918      +/-   ##
==========================================
- Coverage   87.94%   87.92%   -0.02%     
==========================================
  Files          46       46              
  Lines        2132     2129       -3     
==========================================
- Hits         1875     1872       -3     
  Misses        257      257              

Impacted Files	Coverage Δ
src/cordova/platform/addHelper.js	95.83% <ø> (-0.09%)	:arrow_down:

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