docs: update UIAlert usage to keyword arguments and fix dynamic examples (fixes #58089)

[A6AN]

What
Updated the customize-ui.rst examples to use the modern UIAlert API:

Import from airflow.api_fastapi.common.types

Use keyword arguments (text, category) instead of positional usage

Updated static and dynamic alert examples accordingly

Why
The old examples used the previous import path and positional arguments.
The new API requires keyword arguments and lives under api_fastapi.common.types.

Changes

Updated Basic Static Alerts section

Updated Dynamic Alerts example (yield UIAlert(...))

Added clarification note

Fixes #58089.

[A6AN]

Hi folks I updated the Customize UI docs to use the current UIAlert API:

• Import from airflow.api_fastapi.common.types
• Use keyword arguments (text, category) in static and dynamic examples
• Added a short clarifying note

PR: #58540

Two small asks:

1. Could a maintainer please approve the workflow runs so CI can complete? (This is a fork PR.)
2. Could someone on the docs team take a quick look? I’ll push any tiny wording/formatting fixes immediately.

Thanks!
Ayan

[pierrejeambrun]

Thanks for the PR.

Closing as it was already fixed by #58090. (I was not aware of the related issue and this PR at the time)

The PR looks mostly ok but there are a lot of changes that are unrelated to the bugfix and it would have required more work to be mergeable.