bug-2052944: add Glean client ID as a protected field

[biancadanforth]

Because:

• We need the Glean client ID from crash pings to process Firefox telemetry data deletion requests as required per Bug 2052950.

This commit:

• Adds the Glean client ID to the raw and processed crash schema, linking them via the source_annotation which ensures the field is copied into the processed crash via the CopyFromRawCrashRule in the processor.
• Indexes the new field as a keyword to ensure we can search for exact matches when processing data deletion requests.

Notes:

• As indicated in the raw crash schema changes, I obtained a datareview+ in the ticket.
• Since this field is only used for processing data deletion requests, I did not explicitly add it to any of the Crash Stats UIs.
• We have general tests that cover a lot of the mechanisms that I get "for free" in this patch: copying from the source annotation, asserting the field gets indexed, redacting the field in specific cases, ... I decided to add a couple of new tests specifically for this field to cover the critical processor and search behavior, though there is some overlap with existing tests. I couldn't find a good, recent reference patch for this class of new field (protected, based on a source annotation).

[smarnach]

Looks good to me.