Remove obsolete Firestore validation tests

[AlmostMatt]

Description

Firestore implementation has been updated such that the validation no longer rejects use of multiple array-contains filters.
https://github.com/firebase/firebase-ios-sdk/pull/10449/files#diff-e11c1c8fc02726cb87283757008e935497911ea74a41f0efa93c4d2d6517d050

So this PR removes a test that expected this to throw an exception.
Example of a failure of the test before this change:
https://github.com/firebase/firebase-cpp-sdk/actions/runs/4242014548/jobs/7373657438

---

Testing

Describe how you've tested these changes. Link any manually triggered Integration tests or CPP binary SDK Packaging Github Action workflows, if applicable.

---

Type of Change

Place an x the applicable box:

• Bug fix. Add the issue # below if applicable.
• New feature. A non-breaking change which adds functionality.
• Other, such as a build process or documentation change.

---

Notes

• Bug fixes and feature changes require an update to the Release Notes section of release_build_files/readme.md.
• Read the contribution guidelines CONTRIBUTING.md.
• Changes to the public API require an internal API review. If you'd like to help us make Firebase APIs better, please propose your change in a feature request so that we can discuss it together.

[github-actions]

Integration test with FLAKINESS (succeeded after retry)

Requested by @AlmostMatt on commit d2776f0
Last updated: Fri Feb 24 15:36 PST 2023
View integration test log & download artifacts

Failures	Configs
firestore	[TEST] [FLAKINESS] [Android] [1/3 os: windows] [1/2 android_device: android_target] (1 failed tests)   CRASH/TIMEOUT

Add flaky tests to go/fpl-cpp-flake-tracker