Add source filter support in bot search feature

[ShivCharanSharma]

Feat: Add source filter support in AskGurbaniBot search | Fixes #1828

Summary

This PR fixes issue #1828 by adding source selection support to the Ask GurbaniBot modal and ensuring its search state is fully isolated from the main site search (header/SearchForm) state.

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Changes

✨ feat: Add source selection to AskGurbaniBot search

• Added a source selector (<select>) inside AskGurbaniBotQuestionModal so users can filter which Gurbani source the bot searches from.
• Updated AskGurbaniBotSearch to accept and pass the selected source value through to the bot API query.
• Pass the selected source from the modal to the SearchResults component for the bot search.

🔒 feat: Isolate bot search state from main/normal search state

• Introduced an isolateFromLocalStorage boolean prop on SearchForm to prevent the bot's form state (type, source, writer) from being read from or written to localStorage.
• The AskGurbaniBotQuestionModal now passes isolateFromLocalStorage to its SearchForm, keeping the bot's selections completely independent of the main header search.
• Added centralized saveToLocalStorage and removeFromLocalStorage helper methods inside SearchForm that respect the isolateFromLocalStorage flag — all existing localStorage calls now route through these helpers.
• The main/header search state and local storage preferences are no longer affected when a user interacts with the GurbaniBot search.

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Files Changed

File	Change
src/js/components/Modals/AskGurbaniBotQuestionModal.tsx	Added source selector UI; added isolateFromLocalStorage prop
src/js/components/SearchResults/AskGurbaniBotSearch.tsx	Wired source prop through to the bot API
src/js/components/SearchForm.js	Added isolateFromLocalStorage prop & localStorage helper methods
src/js/components/Header.js	Minor formatting/indentation cleanup

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• Passed sanity tests.
  • Checked the sanity tests that, for which I was able to find input or elements
• Ran npm test & fixed newly introduced lint errors.
• Checked console for errors.
  • I found 3 existing console warning in dev branch, and these are unrelated to changes in this PR, please let me if I should fix those too, by creating a new PR
    • Failed prop type: Invalid propdefaultAutoDetectGurmukhiof typebooleansupplied toSearchForm, expected string.
    • Warning: validateDOMNesting(...): <button> cannot appear as a descendant of <button>. Error Component Stack for FloatingActions
    • installHook.js:1 Warning: Each child in a list should have a unique "key" prop. in HomePageIcons

Testing

• Open the Ask GurbaniBot modal, change the source, and confirm the header search source is not affected.
• Use the GurbaniBot with a specific source and verify results are filtered accordingly.

Demo Video

https://drive.google.com/file/d/1C_t8AA7QLJFOmsoQiZ5cgFZUWsaOCWsP/view?usp=sharing

npm test output

Updated UI screenshots