chore(telemetry): renew metrics (and remove some)

[fiji-flo]

Summary

dropping: userAgent, viewportRatio and viewportHorizontalCoverage
renew: everything else

[fiji-flo]

Request for Data Collection Renewal

** This form is for the renewal of an existing, reviewed data collection.**

** All questions are mandatory.
You must receive Data Review from a
Data Steward
on a filled-out Request before shipping your renewed data collection.**

1. Provide a link to the initial Data Collection Review Request for this collection.
   MP-9 Integrate Glean.js MDN #6813 (comment)
2. When will this collection now expire?
   2025-09-05
3. Why was the initial period of collection insufficient?
   These are our core metrics we keep reporting on.

Tagging @chutten and @wagnerand for review.

[chutten]

DATA REVIEW RESPONSE:

Is the provided Data Collection Review complete, correct, and data-review+ by a Data Steward?

Yes.

Is the data collection covered by the existing Firefox Privacy Notice?

Yes.

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Result: datareview+