Feat(notetaker): hide selected text from searchbar + handle edge cases for AI selection context

[adityanandanx]

Description

• Hide the text added via selection from the searchbar
• (not needed anymore) Refactor code so as to use react states instead of using the Highlight extension for storing selection content
• Create custom extension for accepting and declining the generated content.

Checklist before requesting a review

Please delete options that are not relevant.

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented hard-to-understand areas
• I have ideally added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged

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