Editable Combobox with Grid Popup Example, Home and End keys do not have expected behavior on macOS

[stalgiag]

Overview

While working on #3115, I discovered an issue with the Editable Combobox with Grid Popup Example on macOS. The Home and End keys move focus back to the textbox input but do not change the cursor index in the field on macOS.

Testing Instructions

We can use the steps from the "Home from focus on list ..." test on the example linked above.

1. Focus on the textbox
2. Type the key "a"
3. Type the key "down arrow"
4. Type the key "home"

Expectation

The popup should be closed and the cursor should be at the beginning of the textbox input. This is according to the example itself which states that the Home key "Moves focus to the textbox and places the editing cursor at the beginning of the field". This behavior has been observed by multiple testers on various versions of macOS from 13 and 15 using Chrome, Safari, and Firefox. It works as expected on Windows.

Side Note

This is handled for local testing and documented in the relevant test with this commit in #3115