Use Functions to send test Messages via v1 method

[a-maurice]

Description

Provide details of the change, and generalize the change in the PR title above.

Update the Messaging tests to send messages via Cloud Functions to use the new v1 method of sending messages, since the old method is deprecated.

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Testing

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

Running tests manually

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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.

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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 @a-maurice on commit c517451
Last updated: Fri May 31 13:11 PDT 2024
View integration test log & download artifacts

Failures	Configs
app_check	[TEST] [FLAKINESS] [Android] [1/3 os: macos] [1/2 android_device: emulator_ftl_target] (1 failed tests)   FirebaseAppCheckTest.TestFunctionsSuccess
firestore	[TEST] [FLAKINESS] [Android] [1/3 os: macos] [1/2 android_device: emulator_ftl_target] (1 failed tests)   AggregateCountTest.TestKeyOrderIsDescendingForDescendingInequality

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