Upgrade Firestore Emulator to 1.8.2

[schmidt-sebastian]

This should fix the CI failure in #2128

1.5.0 returns the following response to a delete of a non-existing doc:

Firestore (6.4.0) [Connection]: GRPC stream sending: { streamToken: <Buffer 30>,
  writes: 
   [ { delete: 'projects/test-emulator/databases/(default)/documents/test-collection/8ZFesMAbTQGIuVox8P17' } ] }
Firestore (6.4.0) [Connection]: GRPC stream received: { writeResults: 
   [ { transformResults: [], updateTime: { seconds: '0', nanos: 0 } } ],
  streamId: '',
  streamToken: <Buffer 31>,
  commitTime: { seconds: '0', nanos: 0 } }

I believe newer version now return a proper commit and update time.