fix(config-migration): skip migration of package.json

[RahulGautamSingh]

Changes

1. If config is present in package.json and migration is need:
   Prev: Add checkbox on dependency dashboard and if the user checks it create a migration PR (faulty PR)
   Now: No checkbox on dashboard instead a warning message is shown there asking the user to migrate to a dedicated config file

2. If config is present in package.json and migration is needed and a faulty pr exists
   After this PR is merged, such open PRs will be closed and warning will be added on dashboard asking user to migrate to a dedicated config file

Context

• Closes: "Migrate Renovate Config" PR should not apply to package.json contents #33116

Documentation (please check one with an [x])

• I have updated the documentation, or
• No documentation update is required

How I've tested my work (please select one)

I have verified these changes via:

• Code inspection only, or
• Newly added/modified unit tests, or
• No unit tests but ran on a real repository, or
• Both unit tests + ran on a real repository pt1-repro pt2-repro

[renovate-release]

🎉 This PR is included in version 39.69.3 🎉

The release is available on:

• GitHub release
• npm package (@latest dist-tag)
• 39.69.3

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