[Group Chats] Fix UI/UX of the "Add/remove from group" modal

[noeliaSD]

We need to fix the UI/UX of the "Add/remove from group" modal to make it usable on mobile:

[sunleos]

@noeliaSD, checked on release v2.36, I can open that add member modal

• Status desktop version: build 3 from Fix/disable swap on ios #19306
• Operating System: Android 15

[noeliaSD]

@Rsttskyy we need some quick fix for that to make it usable on mobile. It's really difficult to add / remove member from a group chat.

[Rsttskyy]

as quickest solution I would love to move input on the second line, and keep save changes separately from cancel.
https://www.figma.com/design/SGyfSjxs5EbzimHDXTlj8B/Qt-Responsive---v?node-id=3233-100977&t=EjAykqYrBzc9Aahl-1

[Rsttskyy]

in case of overflow with member-buttons would be great to expand input container by height, if it takes a lot of time from efforts, we can put input field on the next line after buttons by Y-axis