This tweaks the appearance of the existing 3PID management UX to use a different
style for the remove button. This styling will more closely match the soon to be
added 3PID discovery settings.
Part of https://github.com/vector-im/riot-web/issues/10159
As part of adding validation to Field, the logic is simpler to follow if we can
assume that all usages of Field use it as a controlled component, instead of
supporting both controlled and uncontrolled.
This converts the uncontrolled usages to controlled.
This fixes an unrelated bug where the currently selected country's prefix number
wasn't being displayed. Since other country dropdown's show the prefix, and this
is also for phone numbers, it seems good to also show it here as well.
These icons are based on Feather as the original source, but they have various
tweaks applied, such as stroke width, color, etc. Hopefully the tweaked name
makes this more obvious in the future.
