Select field in modal dialog has jumpy focus

Problem/Motivation

Original report: #3023777-28: datetime_range fields have confusing options for date type setting

If you are interacting with a select element within a dialog modal by keyboard with VoiceOver enabled, as soon as you are trying to expand the option list of a select element for a second time by pressing the space bar the focus jumps to the Change field type button.

That is not in line with WCAG SC 3.2.1 On Focus (Level A).

For an example, see jumpy_focus.mp4 - recorded with the main branch checked out.

Steps to reproduce

TBD

Proposed resolution

Remaining tasks

User interface changes

Introduced terminology

API changes

Data model changes

Release notes snippet