Bug 1972437: Add metrics when deleting undecryptable logins

[skhamis]

Before we call delete_undecryptable_records_for_remote_replacement for logins, we should add metrics so we can track how many are actually being deleted (and also eventually have confidence in removing said logic once that number goes ~0).

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[skhamis]

Data Request

1. What questions will you answer with this data? How many unencryptable logins were detected and deleted and if it's an ongoing issue.

2. Why does Mozilla need to answer these questions? Are there benefits for users? Do we need this information to address product or business requirements? Some example responses:

The benefits for the users is we're able to understand the severity of the issue and see the trends in unencryptable logins to better understand if we need to make additional changes.

3. What alternative methods did you consider to answer these questions? Why were they not sufficient? No alternatives.

4. Can current instrumentation answer these questions? No.

5. List all proposed measurements and indicate the category of data collection for each measurement, using the Firefox data collection categories found on the Mozilla wiki.

Note that the data steward reviewing your request will characterize your data collection based on the highest (and most sensitive) category.

Measurement Description	Data Collection Category	Tracking Bug #
We've detected undecryptable login records and they haven't ran a deletion before. Since we're counting deleting logins that can't be decrypted, I've kept it at technical	Category 1 “Technical data”	https://bugzilla.mozilla.org/show_bug.cgi?id=1972437

6. Please provide a link to the documentation for this data collection which describes the ultimate data set in a public, complete, and accurate way.

• Often the Privacy Notice for your product will link to where the documentation is expected to be.
• Common examples for Mozilla products/services:
  • If this collection is Telemetry you can state "This collection is documented in its definitions files Histograms.json, Scalars.yaml, and/or Events.yaml and in the Probe Dictionary at https://probes.telemetry.mozilla.org."
  • If this data is collected using the Glean SDK you can state “This collection is documented in the Glean Dictionary at https://dictionary.telemetry.mozilla.org/"
• In some cases, documentation is included in the project’s repository.

This collection is documented in the Glean Dictionary at https://dictionary.telemetry.mozilla.org/

7. How long will this data be collected? Choose one of the following:

• I want to permanently monitor this data. (Sammy Khamis, Sync Engineer)

8. What populations will you measure?

All channels in all countries in all locales, for Firefox iOS and Fenix

9. If this data collection is default on, what is the opt-out mechanism for users? Standard Firefox telemetry controls

10. Please provide a general description of how you will analyze this data. Via graphs in Looker/Redash.

11. Where do you intend to share the results of your analysis? Internally to monitor logins sync health.

12. Is there a third-party tool (i.e. not Glean or Telemetry) that you are proposing to use for this data collection? If so: No.

[skhamis]

@travis79, can I ping you for a data-review? I was trying to add data-reviewer but wasn't letting me some reason -- thanks!