Remove inaccurate mention of `ensure-matrix-users-created` in mautrix-bluesky documentation

mautrix bridges run in appservice mode and create their own user
automatically. There's no need for `ensure-matrix-users-created`.

This patch only fixes the mautrix-blusky bridge's documentation.

docs/configuring-playbook-bridge-mautrix-bluesky.md

@@ -35,13 +35,11 @@ After configuring the playbook, run it with [playbook tags](playbook-tags.md) as
 
 <!-- NOTE: let this conservative command run (instead of install-all) to make it clear that failure of the command means something is clearly broken. -->
 ```sh
-ansible-playbook -i inventory/hosts setup.yml --tags=setup-all,ensure-matrix-users-created,start
+ansible-playbook -i inventory/hosts setup.yml --tags=setup-all,start
 ```
 
 **Notes**:
 
-- The `ensure-matrix-users-created` playbook tag makes the playbook automatically create the bot's user account.
-
 - The shortcut commands with the [`just` program](just.md) are also available: `just install-all` or `just setup-all`
 
   `just install-all` is useful for maintaining your setup quickly ([2x-5x faster](../CHANGELOG.md#2x-5x-performance-improvements-in-playbook-runtime) than `just setup-all`) when its components remain unchanged. If you adjust your `vars.yml` to remove other components, you'd need to run `just setup-all`, or these components will still remain installed.