ci: use emulator for firestore 2nd database

[russellwheatley]

Description

• Uses emulator for 2nd database, one of the reasons (amongst others) for flakey tests is the use of live project for firestore 2nd database e2e tests. This ought to improve CI flow.

Blocked

• Contrary to release notes and documentation that doesn't work, emulator support is not there for firestore 2nd database.

Related Issues

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Checklist

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Breaking Change

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