Live location sharing - handle geolocation errors (#8179)

* display live share warning only when geolocation is happening

Signed-off-by: Kerry Archibald <kerrya@element.io>

* kill beacons when geolocation is unavailable or permissions denied

Signed-off-by: Kerry Archibald <kerrya@element.io>

* polish and comments

Signed-off-by: Kerry Archibald <kerrya@element.io>

test/test-utils/index.ts

@@ -1,5 +1,6 @@
 export * from './beacon';
 export * from './client';
+export * from './location';
 export * from './platform';
 export * from './test-utils';
 // TODO @@TR: Export voice.ts, which currently isn't exported here because it causes all tests to depend on skinning