Always generate -webkit-backdrop-filter property

[adamwathan]

This PR updates all of the backdrop-* utilities to always include the -webkit-backdrop-filter vendor prefixed property so that Tailwind isn't completely dependent on autoprefixer or Lightning CSS to produce these styles. We used to do this for -webkit-appearance: none for the same reason until browser support for the unprefixed property was solid.

Safari didn't add support for unprefixed backdrop-filter until Safari 18 (which isn't out yet at the time of this PR), so I think it makes sense to just bake this in. We do this in the v4 engine already which is targets more modern browsers than v3, so I think it makes sense to do in v3 as well:

https://github.com/tailwindlabs/tailwindcss/blob/next/packages/tailwindcss/src/utilities.ts#L3262

Here's an example of where this bit someone in an important situation:

https://x.com/impatienceisav1/status/1811837511544803416