Iframe: move over remaining e2e tests

[ellatrix]

Description

See https://github.com/search?q=repo%3AWordPress%2Fgutenberg%20test%2Fv2&type=code.

In #48286 some tests were not moved over because they turned out to be difficult, such as drag and drop.

Step-by-step reproduction instructions

.

Screenshots, screen recording, code snippet

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Environment info

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Please confirm that you have searched existing issues in the repo.

Yes

Please confirm that you have tested with all plugins deactivated except Gutenberg.

Yes

[Mamaduka]

I think we can close this; all e2e tests should be using iframed editors. Related PRs can be found as references for #74042.