[Session] Add useAgent hook and replace (#3706)

* Hook it up

* Memoize getAgent method

* Use one shared reference

---------

Co-authored-by: Dan Abramov <dan.abramov@gmail.com>

src/state/queries/suggested-feeds.ts

@@ -2,12 +2,13 @@ import {AppBskyFeedGetSuggestedFeeds} from '@atproto/api'
 import {InfiniteData, QueryKey, useInfiniteQuery} from '@tanstack/react-query'
 
 import {STALE} from '#/state/queries'
-import {getAgent} from '#/state/session'
+import {useAgent} from '#/state/session'
 
 const suggestedFeedsQueryKeyRoot = 'suggestedFeeds'
 export const suggestedFeedsQueryKey = [suggestedFeedsQueryKeyRoot]
 
 export function useSuggestedFeedsQuery() {
+  const {getAgent} = useAgent()
   return useInfiniteQuery<
     AppBskyFeedGetSuggestedFeeds.OutputSchema,
     Error,