Missing icon in context menu invoked on page opened in container on macOS (v8.1.4)

[acornestean]

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. Install Multi-Account Container v8.1.4 (release candidate) on macOS
2. Access https://www.wikipedia.org/ in a tab and then open it in a container
3. On the containerized page, right click the page contents to invoke the right click context menu
4. Notice the Multi-Account Containers option is missing the corresponding icon

Actual behavior

The right click context menu invoked on a page opened in a container is missing the icon for the MA-C option.

Expected behavior

The right click context menu option should display the icon/

Additional informations

NOTE 1: The issue occurs only on macOS. On Windows and Linux the icon is displayed.
NOTE 2: The issue occurs with either the Light or Dark theme applied.
NOTE 3: The currently released AMO version of the extension (8.1.3) does not have this issue

Screenshot from 8.1.3:

Screenshot from 8.1.4:

Provide a copy of Troubleshooting Information page (optional)

No response