[genre] Implement subgenre dropdowns for search

[kylezryr]

What's new in this PR

• Added genre, tone, and topic dropdowns on the search screen
• With no search in the search bar, pressing on a genre redirects the user to the corresponding genre page. Tone and topic selectors do nothing
• With a search in the search bar, the user can select multiple tones, topics, or genres to filter search results
• Added a clear filter button to reset all filters and display normal search results
• No styling applied in this PR

Relevant Links

Notion Sprint Task

https://www.notion.so/calblueprint/genre-Implement-subgenre-dropdowns-for-search-cc819b7e16f84b9f9866c474f8f11a2e

Online sources

https://www.npmjs.com/package/react-native-element-dropdown

Related PRs

• Styling subgenre dropdowns

How to review

Next steps

• Styling the dropdowns and the clear filter button, making sure they appear in the correct place

Tests Performed, Edge Cases

• Selected genre still shows in the dropdown after navigating to the genre page and going back to the search page, and persists after closing the search results

Screenshots

subgenre.MP4

CC: @adityapawar1