Switch the upload html bypass to a button

[joedolson]

Removes some additional unused code from previous patch.

Trac ticket: https://core.trac.wordpress.org/ticket/63238

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This Pull Request is for code review only. Please keep all other discussion in the Trac ticket. Do not merge this Pull Request. See GitHub Pull Requests for Code Review in the Core Handbook for more details.

[github-actions]

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Props joedolson, sabernhardt.

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[github-actions]

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[sabernhardt]

This works for me on Windows 11 with Firefox 144 and Chrome 141.

• Both are button elements, and they activate with either the Enter key or the space bar.
• Activating each button moves focus to the appropriate file input or select button.
• After switching the uploader and navigating to another page, it remembers my choice of uploaders.

[github-actions]

A commit was made that fixes the Trac ticket referenced in the description of this pull request.

SVN changeset: 61099
GitHub commit: e0eb90b

This PR will be closed, but please confirm the accuracy of this and reopen if there is more work to be done.