[Feature Request]: Add AI policy to the PR template

[adhiamboperes]

Is your feature request related to a problem? Please describe.

We would like contributors to disclose if they used AI in the PRs they submitted, and to what extent the AI was used.

Describe the solution you'd like

Add a "Disclosure of LLM usage" section right above the "Essential Checklist" section. It should contain two questions:

1. Did you use AI/LLMs when working on this PR? Type Yes or No.
2. Describe the extent AI was used, e.g. brainstorming, debugging, writing code, writing tests, reviewing code etc. Please refer to Fix #5989, #6053, #6059, #6060, #6097, #6200: Rebuild app & WorkManager initialization #6062 for example.

Describe alternatives you've considered

We can also consider emphasizing that we do not discourage LLM usage, but we expect contributors to double-check their work and submit high quality code.

Additional context

No response