Adds a composer prompt on the home screen to invite users to post (#9464)

* Add a composer prompt on home

* Added image upload button

* Feed composer buttons

* Feed composer styles

* Add client events, auto-open gallery when button is pressed

* Add feature gate

* Move gate check to last

* Small style cleanups

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Co-authored-by: Eric Bailey <git@esb.lol>

src/logger/metrics.ts

@@ -203,6 +203,10 @@ export type MetricEvents = {
 
   'composer:gif:open': {}
   'composer:gif:select': {}
+  'postComposer:click': {}
+  'composerPrompt:press': {}
+  'composerPrompt:camera:press': {}
+  'composerPrompt:gallery:press': {}
 
   'composer:threadgate:open': {
     nudged: boolean