MR2 Telemetry: Inactive tabs

[MozillaNoah]

https://mozilla-hub.atlassian.net/browse/FNXV2-18052

Add events for:

• Opening an inactive tab
• Deleting/closing all inactive tabs
• Deleting/closing a single inactive tab
• Whether the inactive tab section is showing
• The count of inactive tabs
• Toggling inactive tabs on/off in Settings

┆Issue is synchronized with this Jira Task

[lobontiumira]

Verified as fixed on the 10/25 Firefox Nightly 95.0a1 with Google Pixel (Android 10).
Glean dashboard

• Opening an inactive tab:

 {
          "timestamp": 41573,
          "category": "tabs_tray",
          "name": "opened_existing_tab",
          "extra": {
            "source": "Inactive tabs"
          }

• Deleting/closing all inactive tabs

 {
          "timestamp": 66710,
          "category": "tabs_tray",
          "name": "close_all_inactive_tabs"
        }

• Deleting/closing a single inactive tab

 {
          "timestamp": 38998,
          "category": "tabs_tray",
          "name": "closed_existing_tab",
          "extra": {
            "source": "Inactive tabs"
          }

• Whether the inactive tab section is showing & the count of inactive tabs

{
          "timestamp": 35736,
          "category": "tabs_tray",
          "name": "has_inactive_tabs",
          "extra": {
            "inactive_tabs_count": "6"
          }

• Toggling inactive tabs on/off in Settings

{
          "timestamp": 7730,
          "category": "home_menu",
          "name": "settings_item_clicked"
        }

• Expand / collapse the inactive tabs

{
          "timestamp": 64127,
          "category": "tabs_tray",
          "name": "inactive_tabs_collapsed"
        }

 {
          "timestamp": 65417,
          "category": "tabs_tray",
          "name": "inactive_tabs_expanded"
        }