[popover][dialog] Use click event for outside press dismissal

[atomiks]

• I have followed (at least) the PR section of the contributing guide.

Closes #2272

Some reasons why this is better:

• It improves accessibility for dialog-like elements, which can have complex content inside and this offers a native way to cancel the dismissal (instead of e.g. explicitly coding it, though that should probably be done anyway for important content)
• Since Dialog.Trigger and Popover.Trigger both open on click, triggering the dismissal on mouseup instead of mousedown makes sense symmetrically and also ensures pressing outside to open a new dialog or popover dismisses the open one at the same time, which feels smoother

Note: this doesn't apply if focus moves outside of the dialog or popover while pressing outside, which causes it to close on mousedown still (due to the focusout event). So if you click a Select trigger, which opens on mousedown, the Popover will also close on mousedown. This is expected anyway since you don't want to the Popover and Select to be open simultaneously during the delay between down and up pointer events.

[pkg-pr-new]

vite-css-base-ui-example

npm i https://pkg.pr.new/@base-ui-components/react@2275

commit: ba1c267

[mui-bot]

Bundle size report

Bundle	Parsed Size	Gzip Size
@base-ui-components/react	▼-2.05KB(-0.67%)	▼-687B(-0.70%)

Details of bundle changes

Generated by 🚫 dangerJS against ba1c267

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