Search: Prevent IE11 from spawning overlay on load

[jsnmoon]

Fixes #19100.

Changes proposed in this Pull Request:

• Prevents the onChange handler from binding to SearchBox when the modal is not visible. This prevents IE11 from triggering an onChange event on window load, which occurs when the input's placeholder contains a Unicode character.

Does this pull request change what data or activity we track or use?

No.

Testing instructions:

• Apply this change to your site with a Jetpack Search subscription.
• Navigate to / in Internet Explorer 11 :)
• Ensure that the search modal does not appear upon loading the page.
• Perform a site search and ensure that the search modal appears as expected.
• Alter the query via the modal search input. Ensure that the interface works as expected.

[matticbot]

Caution: This PR has changes that must be merged to WordPress.com
Hello jsnmoon! These changes need to be synced to WordPress.com - If you 're an a11n, please commandeer and confirm D58577-code works as expected before merging this PR. Once this PR is merged, please commit the changes to WP.com. Thank you!
This revision will be updated with each commit to this PR

[github-actions]

Thank you for your PR!

When contributing to Jetpack, we have a few suggestions that can help us test and review your patch:

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jetpack plugin:

• Next scheduled release: April 6, 2021.
• Scheduled code freeze: March 29, 2021

[bluefuton]

Excellent sleuthing! Works well for me.

[bluefuton]

@jeherve can we nominate this for a point release if there's one planned? (9.5.1?)

[jeherve]

can we nominate this for a point release if there's one planned? (9.5.1?)

We have no point release planned so far, but I'll keep it in mind if something comes up.

[jeherve]

This should be good to merge. I've added a changelog entry with vendor/bin/changelogger add and committed it in ea63974

[github-actions]

Great news! One last step: head over to your WordPress.com diff, D58577-code, and commit it.
Once you've done so, come back to this PR and add a comment with your changeset ID.

Thank you!

[jsnmoon]

r222673-wpcom.

[jeherve]

Cherry-picked to jetpack/branch-9.5 in 3090276