Extensions are not working for firefox

Created by: muratsu

BExt: v21.10.21.1959 Firefox: 94.0.1 (64-bit) - MacOS

Steps to reproduce:

1. Have extensions enabled
2. Navigate to a github repo

Expected behavior:

Extensions to be activated

Actual behavior:

Errors in the logs

Related issue: https://github.com/codecov/sourcegraph-codecov/issues/77