Expose device identifier

### Problem Statement

Sentry uses some internal logic to combine device information into a hash called the `deviceAppHash`, exposed as `app.device` in the crash reports.

Unfortunately, there is no way for the developer to access this identifier directly. Effectively, this is a private data point internal to Sentry.

I would like to gain access to this identifier. It is quite useful when we want to direct our developers to the crash logs for a specific user's device.
Naively, I was building this link as such:
```
"See Sentry: https://hubstaff.sentry.io/issues/?query=app.device%3A\(UIDevice.current.identifierForVendor?.uuidString)"
```
But this doesn't work since Sentry hashes the identifier (alongside potentially some other information).

Ideally Sentry shouldn't manage private data on the user which is hidden from the developer.

### Solution Brainstorm

The device identifier is generated in `Sources/SentryCrash/Recording/Monitors/SentryCrashMonitor_System.m`, stored in a private `g_systemData`, copied into `eventContext->System.deviceAppHash`, written to the crash report's `device_app_hash` in `Sources/SentryCrash/Recording/SentryCrashReport.c`.

Suggest exposing the identifier in `SentrySDK` or `SentryClient`.

### Are you willing to submit a PR?

_No response_