Fix PhoneAuthOptions Timeout overflow on some platforms

[AlmostMatt]

Description

On some platforms there was previously an issue with the code to convert TimeoutMilliseconds from uint32_t to java long, causing it to become a negative value and then getting rejected by Android validation.
Example: firebase/firebase-unity-sdk#764

I was able to reproduce the original issue with the Unity Auth testapp, which calls VerifyPhoneNumber with a PhoneAuthOptions.
The visible error was: "VerifyPhoneNumber: builder faild to create PhoneAuhtOptions"
Looking into the android logcat, the internal error was: "We only support 0-120 seconds for sms-auto-retrieval timeout"

This change should fix this by having an explicit cast from uint32_t to jlong before passing the timeout into the java long constructor. This should make the code work regardless of whether jlong is a 32 bit or 64 bit number.

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Testing

I verified the fix by building the unity sdk with this change included and running the Unity auth testapp. VerifyPhoneNumber ran successfully on my device.

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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 FAILED

Requested by @AlmostMatt on commit cd6c183
Last updated: Mon Jun 26 17:38 PDT 2023
View integration test log & download artifacts

Failures	Configs
firestore	[BUILD] [ERROR] [Android] [1/3 os: ubuntu] [TEST] [ERROR] [Android] [1/3 os: ubuntu] [All 2 android_device]

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

[jonsimantov]

How would this actually occur to a developer using our SDK? Would it always fail or only if they specified a timeout? Probably best to describe this from the developer's perspective.

[AlmostMatt]

The issue was reported by a developer in firebase/firebase-unity-sdk#764.
I tried to phrase the readme description similar to the error message that was shown to the user.

I think it would always fail. VerifyPhoneNumber takes a PhoneAuthOptions which always has a timeout milliseconds field. Regardless of what they set (0 or 60 seconds), it would still overflow to some invalid value and the user gets an error.

That said, when I tested our C++ integration tests VerifyPhoneNumber succeeded even without this fix. I think this must be something like a different compiler that uses 32 bits for a long, and therefore no overflow occured. So the issue might be specific to Unity users.

[jonsimantov]

Ah ok. So maybe add "with certain compiler settings" to the end of the explanation.

[AlmostMatt]

Done