docs: media worker serves client resources

[johannes-krude]

The workers documentation mentions that the media worker can handle the new endpoints for authenticated media, but the included example config misses the client resources.

I spent several hours debugging our synapse deployment and reverse proxy configuration to figure out the reason that element-desktop is no longer able to load avatars and uploaded images.

Without the client resource, the media worker responds with M_UNRECOGNIZED to ^/_matrix/client/v1/media/ requests and element-desktop shows "Unable to show image due to error".

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[anoadragon453]

@johannes-krude did you test with Synapse v1.114+? As of that release, including only media should be enough to enable the authenticated media endpoints. See #17483

[johannes-krude]

I now upgraded to v1.114 and it works now without client.