test: add more electron framework tests for release builds

[karanbirsingh]

Details

In this PR:

• we verify that the electron version and mirror build ID are updated in lockstep (to avoid forgetting the build ID)
• we verify that the executable's electron build ID (found in process.versions) matches what we expect

The update process looks the same, although the assetNumber is moved to its own standalone file.

Motivation

This builds on PRs like #2749 and #2604 to improve the electron-upgrade process.

validation run

see question at https://github.com/microsoft/accessibility-insights-web/pull/4272/files#r638299525

Pull request checklist

• Addresses an existing issue: #0000
• Ran yarn fastpass
• Added/updated relevant unit test(s) (and ran yarn test)
• Verified code coverage for the changes made. Check coverage report at: <rootDir>/test-results/unit/coverage
• PR title AND final merge commit title both start with a semantic tag (fix:, chore:, feat(feature-name):, refactor:). See CONTRIBUTING.md.
• (UI changes only) Added screenshots/GIFs to description above
• (UI changes only) Verified usability with NVDA/JAWS

[karanbirsingh]

I thought about running this only in PR builds, but I'm not sure. On one hand it'll simplify electron prototyping locally (otherwise folks will need to comment out), but on the other it'll defer issues until PR-time.