Select loading label and empty options text can be selected using a keyboard

[GCHQ-Developer-718]

Summary of the bug

loadingLabel and emptyOptionsListText can be selected as options using the keyboard for a select.

The bug only seems to be reproducible in stackblitz, not the storybook playground, and only seems to affect single, non-searchable select (e.g. <ic-select searchable="false" multiple="false"></ic-select>

🪜 How to reproduce

1. Open the Stackblitz example
2. Focus the select with a keyboard or mouse then use the arrow keys to open it and select the loadingLabelText, as if it's an option. You should be able to reproduce the first screenshot below.
3. Remove the loading prop and repeat. You should be able to reproduce the second screenshot below.

📸 Screenshots or code

📝 Acceptance Criteria

1. loadingLabel and emptyOptionsListText cannot be selected as options using any input method
2. Bug is not present when components are used in a local test project (not just storybook playground)