[APP-657] Add share list functionality (#863)

* replace delete list button text with icon

* fix mute list styling on desktop

* add share button to nav bar on a list

* fix styling when on profile

* bug: add key to ImageHorzList

* clean up code & refactor

* fix styling for ListItems

* create a reusable ListActions component for actions on a list

* remove dead styles

* add keys to ListActions

* add helpers to set list embed

* render list embeds

* fix list sharing on web

* make style prop optional in ListCard

* update `@atproto/api` to `0.3.13`

src/state/models/content/list.ts

@@ -97,6 +97,10 @@ export class ListModel {
     return this.list?.creator.did === this.rootStore.me.did
   }
 
+  get isSubscribed() {
+    return this.list?.viewer?.muted
+  }
+
   // public api
   // =