"Close Other Tabs" and "Close Tabs Underneath" options do not warn users and close tabs directly

[SoftVision-CiprianMuresan]

[Affected versions]:

• Firefox 57 and up

[Affected Platforms]:

• All Windows
• All Mac
• All Linux

[Prerequisites]:

• Tab Center Redux was previously installed on a clean new Firefox profile.
• Tab sidebar is opened.

[Steps to reproduce]:

1. Open the browser with the profile from prerequisites.
2. Open more than 2 tabs.
3. Right click one of the tabs from the sidebar.
4. Click the "Close Other Tabs" option.
5. Observe the behavior.

[Expected results]:

• A dialog box appears asking the user if he is sure that he wants to close "x" tabs.

[Actual results]:

• All other tabs are closed.

[Notes]:

• The issue is also reproducible with the "Close Tabs Underneath" option.
• The issue is not reproducible if I choose the same option from Firefox's own tab strip.
• Attached a screen recording of the issue:

[Keith94]

Dupe of #93?

Web Extensions have no way of reading Firefox preferences.

[SoftVision-CiprianMuresan]

More than likely, thanks for pointing that out.