feat(auto-metrics): Add experimental auto game-metrics collection

[mujacica]

Added experimental auto game-metrics. When enabled, the SDK periodically collects common performance metrics and sends them to Sentry via the metrics API.

[github-actions]

	Fails
🚫	Please consider adding a changelog entry for the next release.

	Messages
📖	Do not forget to update Sentry-docs with your feature once the pull request gets approved.

Instructions and example for changelog

Please add an entry to CHANGELOG.md to the "Unreleased" section. Make sure the entry includes this PR's number.

Example:

## Unreleased

### Features

- Add experimental auto game-metrics collection ([#2777](https://github.com/getsentry/sentry-unity/pull/2777))

If none of the above apply, you can opt out of this check by adding #skip-changelog to the PR description or adding a skip-changelog label.

Generated by 🚫 dangerJS against 6112c98

[cursor]

Cursor Bugbot has reviewed your changes and found 2 potential issues.

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^{Reviewed by Cursor Bugbot for commit cb420b7. Configure here.}

[cursor]

Corrupted failed-request status codes

High Severity

FailedRequestStatusCodes gained a stray trailing i in its Unity hex payload (f401000057020000i). That corrupts the serialized List<int> and can break options loading when ranges are rebuilt pairwise during SDK init.

 

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[sentry]

Bug: The use of as ulong? to unbox a ulong returned from reflection will always result in null, causing the network ping metric to be silently lost.
_{Severity: MEDIUM}

Suggested Fix

Replace the as ulong? operator with an explicit cast to correctly unbox the value. The line should be changed to return (ulong?)getCurrentRtt.Invoke(transport, new object[] { ServerClientId });.

Prompt for AI Agent

Review the code at the location below. A potential bug has been identified by an AI
agent. Verify if this is a real issue. If it is, propose a fix; if not, explain why it's
not valid.

Location: src/Sentry.Unity/Metrics/NetworkMetricsMonitor.cs#L133

Potential issue: In `NetworkMetricsMonitor.cs`, the code uses reflection to get the
current Round-Trip Time (RTT) via `getCurrentRtt.Invoke(...)`. This method returns a
boxed `ulong`. The code then attempts to unbox this value using the `as ulong?`
operator. According to C# semantics, the `as` operator will return `null` when
attempting to unbox a value type to its nullable counterpart, instead of performing the
unboxing conversion. As a result, the check `rtt.HasValue` on the following line will
always be false, and the ping metric will be silently dropped instead of being reported
to Sentry.

_{Did we get this right? 👍 / 👎 to inform future reviews.}