Add ListComboBox

[hamen]

Overview

This PR contains new components that are meant to replace the Dropdown composable.

ListComboBox

This is the simplest way to create an editable dropdown menu that shows a list and allows adding a value that is not present in the list. The API is very minimal to keep things "nice and easy":

public fun ListComboBox(
    items: List<String>,
    listItemContent: @Composable (String, Boolean, Boolean) -> Unit,
)

ComboBox

This is one of the building blocks and represents the editable version of the dropdown component, containing the empty popup and the editable text field.

NotEditableComboBox

This is one of the building blocks and represents the editable version of the dropdown component, containing the empty popup and the text label.

SimpleListItem

This is a pre-made composable that can help to create a list ComboBox without stressing over the styling.

PopupContainer

This is the empty popup used by the ComboBox that can be filled with custom composables.

[rock3r]

When testing, I found these issues:

• Dark theme selection colour is wrong (it's the light theme one), at least in standalone
  
• Selection doesn't move with hover
  https://github.com/user-attachments/assets/1c9212d2-2482-42e4-bc9e-d6dbbf84af1d
• In bridge, the caret icon is the wrong size
  
• Text input changes selection when opening the popup, but it shouldn't
  https://github.com/user-attachments/assets/7ff5dd82-617e-4389-b1e7-7c17458a8c62

This is just a quick smoke test. I will not review this PR until these are fixed, as it's bound to introduce more changes (and hopefully not more bugs)