Zones in Channel Detail do not get updated after creating a new one

[michaelbromley]

Describe the bug
When a new Zone is created in the Admin UI, it does not show up in the Channel Detail "default tax zone" select menu. Only refreshing the app makes it show up.

To Reproduce
Steps to reproduce the behavior:

1. Go to Zone list and create a new zone
2. Go to Channel Detail view and click the "default tax zone" select input
3. Note that the newly-created zone is not there

Expected behavior
It should update whatever internal cache is being used.

Environment (please complete the following information):

• @vendure/core version: 2.2.4
• Nodejs version: any
• Database (mysql/postgres etc): any