Bookmark context menu still uses the old icons (v. 8.3.8) #2913

Before submitting a bug report

• I updated to the latest version of Multi-Account Container and tested if I can reproduce the issue
• I searched for existing reports to see if it hasn't already been reported

Step to reproduce

1. Go to about:config and enable the Nova redesign
2. Install MAC 8.3.8
3. Go to the extension options page in about:config and enable the "Enable Bookmarks Menu" optional permission
4. Bookmark a random page
5. Right click the toolbar and select the "Always show" option from the Bookmarks Toolbar menu (to have easier access to the previously bookmarked page)
6. Right click the page that was bookmarked at Step (4) (the bookmark is shown on the bookmarks toolbar) to open the context menu
7. Hover over the "Open Bookmark in Container Tab" item in the context menu
8. A list of available containers is shown
9. Notice the containers still use the old icons and not the Nova redesigned ones

Actual behavior

The M-AC bookmark context menu still uses the old icons

Expected behavior

The M-AC bookmark context menu should use the new redesigned icons

Additional informations

Affected versions: Nightly 154

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