For #18856: Add metrics for opening settings screen from home menu.

[mcarare]

Pull Request checklist

• Tests: This PR includes thorough tests or an explanation of why it does not
• Screenshots: This PR includes screenshots or GIFs of the changes made or an explanation of why it does not
• Accessibility: The code in this PR follows accessibility best practices or does not include any user facing features. In addition, it includes a screenshot of a successful accessibility scan to ensure no new defects are added to the product.

To download an APK when reviewing a PR:

1. click on Show All Checks,
2. click Details next to "Taskcluster (pull_request)" after it appears and then finishes with a green checkmark,
3. click on the "Fenix - assemble" task, then click "Run Artifacts".
4. the APK links should be on the left side of the screen, named for each CPU architecture

[mcarare]

Request for data collection review form

All questions are mandatory. You must receive review from a data steward peer on your responses to these questions before shipping new data collection.

1. What questions will you answer with this data?
   This will help us understand user interaction with the settings option from the home menu and also count the number of times the settings screen is displayed.

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:
   Determine how many people interact with this option.

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

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.

Measurement Description	Data Collection Category	Tracking Bug #
User clicks on settings item in home menu default browser	category 2 - interaction data	#18856

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.
   https://github.com/mozilla-mobile/fenix/blob/master/docs/metrics.md

7. How long will this data be collected? Choose one of the following:
   2021-10-01

8. What populations will you measure?
   All channels.

9. If this data collection is default on, what is the opt-out mechanism for users?
   Default Glean SDK opt-out mechanism.

10. Please provide a general description of how you will analyze this data.
    Glean / Amplitude

11. Where do you intend to share the results of your analysis?
    Only on Glean, Amplitude and with mobile teams.

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

[mcarare]

Tagging @tdsmith for data review.

Note: I thought about using the existing browser_menu_action event for tracking this also, but the implementation is targeted for the browser menu and it would provide false data if we couldn't discern between the 2 events.

So, for the default browser experiment, both browser_menu_action with settings extra key and settings_item_clicked should be taken into account.

[tdsmith]

Makes sense, thank you! data-review+

1. Is there or will there be documentation that describes the schema for the ultimate data set in a public, complete, and accurate way?

Yes, in the probe definition files and the Glean probe dictionary.

2. Is there a control mechanism that allows the user to turn the data collection on and off?

Yes, the Firefox telemetry opt-out.

3. If the request is for permanent data collection, is there someone who will monitor the data over time?

n/a

4. Using the category system of data types on the Mozilla wiki, what collection type of data do the requested measurements fall under?

Cat 2, interaction data.

5. Is the data collection request for default-on or default-off?

Default-on.

6. Does the instrumentation include the addition of any new identifiers (whether anonymous or otherwise; e.g., username, random IDs, etc. See the appendix for more details)?

No.

7. Is the data collection covered by the existing Firefox privacy notice?

Yes.

8. Does there need to be a check-in in the future to determine whether to renew the data?

The team is responsible for renewing the probe as needed.

9. Does the data collection use a third-party collection tool?

No.