fix(lint): no-html-link in appDir (#68770)
supersedes #51783
## What
This PR fixes the issue of `<a>` tags for internal routing not being
caught by linting in the app directory.
## Why
The linting of the html links should be consistent across pages and app
directories.
## How
- Added a new function to parse the URLs in the appDir (since it's a bit
different from the /pages directory)
- Lint now checks against pagesUrls and appUrls
- Added tests for the appDir in the no-html-link-for-pages test file
fixes #51742
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Co-authored-by: JJ Kasper <jj@jjsweb.site>
