Bugzilla

As we bring tab context menus to consistency, we would like to add a Share submenu on Linux:
- Position: below _Bookmark Tab..." if browser.tabs.notes.enabled = false (Tab Notes are not activated via Firefox Labs or a pref flip); Below  _Add Note_ if Notes are activated; 
- Share menu sub-options for a single tab: _Copy Link_ ; _Generate QR code_ 
- Sub-options for multiple tabs selected: _Copy X Links_; Generate QR code should be greyed out

As we bring tab context menus to consistency, we would like to add a Share submenu on Linux:
- Position: below _Bookmark Tab..._ if `browser.tabs.notes.enabled = false` (Tab Notes are not activated via Firefox Labs or a pref flip); Below  _Add Note_ if Notes are activated; 
- Share menu sub-options for a single tab: _Copy Link_ ; _Generate QR code_ 
- Sub-options for multiple tabs selected: _Copy X Links_; Generate QR code should be greyed out

As we bring tab context menus to consistency, we would like to add a Share submenu on Linux:
- Position: below _Bookmark Tab..._ if `browser.tabs.notes.enabled = false` (Tab Notes are not activated via Firefox Labs or a pref flip); Below  _Add Note_ if `browser.tabs.notes.enabled = true` (Notes are activated); 
- Share menu sub-options for a single tab: _Copy Link_ ; _Generate QR code_ 
- Sub-options for multiple tabs selected: _Copy X Links_; Generate QR code should be greyed out

As we bring tab context menus to consistency, we would like to add the `Share` submenu to the tab context menu on Linux:
- **Position:** below _Bookmark Tab..._ if `browser.tabs.notes.enabled = false` (Tab Notes are not activated via Firefox Labs or a pref flip); Below  _Add Note_ if `browser.tabs.notes.enabled = true` (Notes are activated); 
- _Share_ menu sub-options for **a single tab**: _Copy Link_ ; _Generate QR code_ 
- Sub-options for **multiple tabs selected**: _Copy X Links_; Generate QR code should be greyed out

As we bring tab context menus to consistency, we would like to add the `Share` submenu to the tab context menu on Linux:
- **Position:** below _Bookmark Tab..._ if `browser.tabs.notes.enabled = false` (Tab Notes are not activated via Firefox Labs or a pref flip); Below  _Add Note_ if `browser.tabs.notes.enabled = true` (Notes are activated); 
- _Share_ menu sub-options for **a single tab**: _Copy Link_ ; _Generate QR code_ 
- Sub-options for **multiple tabs selected**: _Copy X Links_; Generate QR code should be greyed out

Telemetry: 
We currently use metric [browser.ui.interaction.tabs_context](https://dictionary.telemetry.mozilla.org/apps/firefox_desktop/metrics/browser_ui_interaction_tabs_context) to record interactions with the tab context menu.
Let's please continue using this one and record the following labels for this metric: 
- click on the top-level Share option | label:` tab-context-share-url` (we already record it on Windows and macOS)
- copy single link | label: `context-copy-url` | [was implemented for macOS in 150](https://bugzilla.mozilla.org/show_bug.cgi?id=2020865)
- copy multiple links | label: `copy-multiple-links`  [was implemented for macOS in 150](https://bugzilla.mozilla.org/show_bug.cgi?id=2020865)
- generate qr code | label: `generate-qr-code` (there's [a separate counter implemented for this action]([url](https://dictionary.telemetry.mozilla.org/apps/firefox_desktop/metrics/qrcode_opened)), but it seems to be useful to track this within this metric)

As we bring tab context menus to consistency, we would like to add the `Share` submenu to the tab context menu on Linux:
- **Position:** below _Bookmark Tab..._ if `browser.tabs.notes.enabled = false` (Tab Notes are not activated via Firefox Labs or a pref flip); Below  _Add Note_ if `browser.tabs.notes.enabled = true` (Notes are activated); 
- _Share_ menu sub-options for **a single tab**: _Copy Link_ ; _Generate QR code_ 
- Sub-options for **multiple tabs selected**: _Copy X Links_; Generate QR code should be greyed out

Telemetry: 
We currently use metric [browser.ui.interaction.tabs_context](https://dictionary.telemetry.mozilla.org/apps/firefox_desktop/metrics/browser_ui_interaction_tabs_context) to record interactions with the tab context menu.
Let's please continue using this one and record the following labels for this metric: 
- click on the top-level Share option | label:` tab-context-share-url` (we already record it on Windows and macOS)
- copy single link | label: `context-copy-url` | [was implemented for macOS in 150](https://bugzilla.mozilla.org/show_bug.cgi?id=2020865)
- copy multiple links | label: `copy-multiple-links` | [was implemented for macOS in 150](https://bugzilla.mozilla.org/show_bug.cgi?id=2020865)
- generate qr code | label: `generate-qr-code`| there's [a separate counter implemented for this action]([url](https://dictionary.telemetry.mozilla.org/apps/firefox_desktop/metrics/qrcode_opened)), but it seems to be useful to track this within this metric