Allow 'self' CSP connect-src by default

[diracdeltas]

fix #13499

test plan:

1. do a packaged build
2. translations should work in it
3. translations should also work in development mode

Submitter Checklist:

• Submitted a ticket for my issue if one did not already exist.
• Used Github auto-closing keywords in the commit message.
• Added/updated tests for this change (for new code or code which already has tests).
• Ran git rebase -i to squash commits (if needed).
• Tagged reviewers and labelled the pull request as needed.
• Request a security/privacy review as needed. (Ask a Brave employee to help if you cannot access this document.)

Test Plan:

Reviewer Checklist:

• Request a security/privacy review as needed if one was not already requested.

Tests

• Adequate test coverage exists to prevent regressions
• Tests should be independent and work correctly when run individually or as a suite ref
• New files have MPL2 license header

[bsclifton]

With latest commit, both running locally and running packaged build works great! 😄 👍 Thanks!

[bsclifton]

master 5f796c8
0.23.x 33c3e84
0.22.x 47bce70