Warn user about tokens in the Issue & MR Description

Related issue: #368434 (closed)

What does this MR do and why?

This MR shows a confirmation warning when user add Issue/MR description with potential sensitive tokens. This change also affects user updating these descriptions.

Note: This follows similar approach to !114621 (merged) & !115493 (merged).

Screenshots or screen recordings

Screen_Recording_2023-03-29_at_1.38.05_PM

How to set up and validate locally

1. Create a new Issue
2. Add issue description with a potential token, for example: "This description contains a token: glpat-1234567890abcdefghij".
3. A confirmation warning should be shown when you submit the form

The same steps can be taken for creating or updating MR description.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.