feat: Ability to remove inbox avatar (#2885)

* Delete inbox avatar

1) New API endpoint added for deleting inbox avatar.
2) Delete avatar button in the inbox settings page.

Co-authored-by: Sojan Jose <sojan@pepalo.com>
Co-authored-by: Muhsin Keloth <muhsinkeramam@gmail.com>

app/javascript/dashboard/store/modules/inboxes.js

@@ -173,6 +173,13 @@ export const actions = {
       throw new Error(error.message);
     }
   },
+  deleteInboxAvatar: async (_, inboxId) => {
+    try {
+      await InboxesAPI.deleteInboxAvatar(inboxId);
+    } catch (error) {
+      throw new Error(error);
+    }
+  },
 };
 
 export const mutations = {