Reinstate/add showPicker() tests

[foolip]

For Forms, we originally had show-picker.html and show-picker-cross-origin-iframe.html labeled for Interop 2022.

In discussion with @ziransun we found that show-picker.html has since been renamed (web-platform-tests/wpt#33465) and then accidentally dropped from the test list in web-platform-tests/wpt-metadata@6eea9fe.

Reinstating the renamed test is probably uncontroversial, but @ziransun has also added a new test so I'd like to suggest adding both. Here they are:

https://wpt.fyi/results/html/semantics/forms/the-input-element?label=master&label=experimental&product=chrome&product=firefox&product=safari&aligned&q=show-picker

show-picker-user-gesture.html is the original test renamed, while show-picker-disabled-readonly.html is the new test, with failures in Chrome and Safari.

[foolip]

@josepharhar can you check out the show-picker-disabled-readonly.html tests and see if including that in Interop 2022 would be reasonable?

[foolip]

@jgraham @gsnedders could you find the right people to weigh in on this for Gecko and WebKit?

[josepharhar]

If we already have/had showPicker tests in interop2022, I don't see anything wrong with including all three of the showPicker tests in the link.
It looks like the new disabled-readonly test was specced here, so I don't think there would be any contention over including it: whatwg/html#7769

[foolip]

Thanks @josepharhar!

[gsnedders]

accidentally dropped from the test list in web-platform-tests/wpt-metadata@6eea9fe

On the whole, I'm in favour of re-adding it given it was accidentally removed. It was there at the start of Interop 2022, and it isn't now.

[jgraham]

This seems fine.

[foolip]

The two additional tests were labeled in web-platform-tests/wpt-metadata#2813.