zilencer: Fix missing decorators on remote_server_dispatch.
zilencer: Fix missing decorators on remote_server_dispatch.

In 5c49e4ba06f3a515f2c141c2f6344b3e6af8e613, we neglected to include
the CSRF and caching decorators required for all API views in the new
remote_server_dispatch function.

I'm not sure why our automated tests didn't catch this, but this made
the remote server API endpoints nonfunctional in a production
environment.

rht/zulip,andersk/zulip,andersk/zulip,zulip/zulip,andersk/zulip,andersk/zulip,zulip/zulip,rht/zulip,andersk/zulip,rht/zulip,rht/zulip,rht/zulip,andersk/zulip,zulip/zulip,zulip/zulip,zulip/zulip,zulip/zulip,andersk/zulip,rht/zulip,zulip/zulip,rht/zulip