appium config: fix validation for address field

[boneskull]

See #18690

The address field in the Appium config is a string which can be formatted as a hostname or an ipv6 (per the JSON schema formatting parlance). Unfortunately, there seems to be a bug in json-schema-to-typescript where the ipv6 formatter does not translate correctly to a TS string; instead, it outputs {[key: string]: unknown}.

1. Report bug to upstream
2. Fix bug, send PR
3. Update to new release

alternatively:

• Implement some sort of workaround for validation; create a new custom formatter in lib/schema/cli-transformers.js and add the appiumCliTransformer prop with the new transformer name to the address object in appium-config-schema.js. It doesn't need to actually transform the value, but it can be used as a validator.

cc @mykola-mokhnach