delete did-detach block accidentally brought back in #14734

[evq]

fixes #15019

a block removed in the single webview project was added back in due to a rebase issue

see discussion here:
https://github.com/brave/browser-laptop/pull/14734/files#r202442461

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

[petemill]

Thanks for catching this

[petemill]

I'll merge to master, 0.24, and 0.23 when the CI test finishes

[petemill]

0.24.x c209fbd
0.23.x b433bc2