Language selector: Arrow keys move focus but Enter always selects first option (WCAG 2.1.1

[olavflar]

Description of the bug

Description
When using the language dropdown with keyboard navigation, arrow keys visually move between options, but pressing Enter always selects the first option in the list (e.g., "Arabic"), regardless of which option is highlighted (e.g., "Polish").
Additionally:
The dropdown currently requires Tab to move between items, which does not follow the expected keyboard pattern for a listbox/combobox.
This behavior fails WCAG 2.1.1 (Keyboard) because the component cannot be reliably used with a keyboard.

Steps To Reproduce

Steps to Reproduce
Focus the language selector.
Press Enter to open the dropdown.
Use Arrow Down to highlight a language other than the first (e.g., "Polish").
Press Enter to select the highlighted option.
Observe that the first item ("Arabic") is selected instead.

Additional Information

No response

[olavflar]

Tested this:

Navigation:
Users must be able to tab into the dropdown, use the arrow keys to move through the list of options, and open/close the dropdown with a key press

When using the frontend version 4.21.0-preview.2 and testing locally - this works almost - but when using the arrow keys to move up/down, I have to press tab to be able to select an option. Need to take a deeper look at this.