Pings with `include_client_id: false` still list the glean-core `client_id` `uuid` metric in their metrics list

[chutten]

The "serp-categorization" ping is sent without the client_id, but if you look at its list of contained metrics it includes the default glean-core client_id uuid metric.

This could cause confusion.

(( For the record, I have confirmed that the client_id metric is absent on all pings with include_client_id: false so this is just an inconsistency in Glean Dictionary, not a data fault. ))