Fix admin room processing commands from its own messages

This prevents the #admins:server.name room from processing commands if they are addressed to @conduit:server.name, but they also come from @conduit:server.name.

This fixes conduit thinking the first line of help is an admin command.

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• I ran cargo fmt and cargo test
• I agree to release my code and all other changes of this MR under the Apache-2.0 license