Administration: Update Close icon for dismissible notices.

In #64548, admin notices were restyled to match Gutenberg components more closely. `@wordpress/components` notices use an SVG icon looking like an `x`, for dismissible notices. The old notices use an `x` in a circle, ​Dashicon `dismiss/153`.

With this changeset, the restyled notices now instead use ​Dashicon `no-alt/335` which is closer to the `@wordpress/components` notices.

Follow-up to [61647], [61681].

Props TobiasBg, niravsherasiya7707, mathiaspeguet, noruzzaman, shailu25, mukesh27, huzaifaalmesbah.
Fixes #64805.
See #64548.



git-svn-id: https://develop.svn.wordpress.org/trunk@61876 602fd350-edb4-49c9-b593-d223f7449a82