[Feature]: Add `<datalist>` support to `<uui-input>`

[iOvergaard]

Discussed in #879

^{Originally posted by leekelleher July 30, 2024}
Could we add <datalist> support to the <uui-input> component, please?

I'd noticed that it was missing whilst migrating Contentment's Text Input property-editor, but also just noticed that it could also be used in the CMS backoffice too (for pre-populating webhook's header field).

[leekelleher]

@iOvergaard I've made a PR for this, #1106, but I'm unsure whether it's the correct approach, given that it adds a <datalist> to the Shadow DOM of the <uui-input>, or if there are alternative approaches to support this? 🤔