TP2000-1334 Geo area exclusions front-end validation

[eadpearce]

TP2000-1334 Geo area exclusions front-end validation

Why

• The list of geo area exclusions was not updated to match the members of a group when a group was selected
• This ended up causing errors right at the end of the measure creation journey, wasting a lot of the user's time
• To avoid this we can do filtering on the form fields on the front-end with react components

What

• Replaces the current form field with a react version that filters the exclusions by the selected group in real time
• Form still functions when JS is disabled

Checklist

• Requires migrations? ❌
• Requires dependency updates? ✅ in package.json