[MM-11593] Prevent user to remove from a direct channel (#9251)

* prevent user to remove from a direct channel

* only allow removing of a member in private or public channel

i18n/en.json

@@ -231,6 +231,10 @@
     "id": "api.channel.remove.default.app_error",
     "translation": "Cannot remove user from the default channel {{.Channel}}"
   },
+  {
+    "id": "api.channel.remove_channel_member.type.app_error",
+    "translation": "Cannot remove user from a channel."
+  },
   {
     "id": "api.channel.remove_member.removed",
     "translation": "%v removed from the channel."