getsentry/sentry-java 8.44.0 on GitHub

Add enableStandaloneAppStartTracing option to send app start as a standalone transaction instead of attaching it as a child span of the first activity transaction (#5342)
- Disabled by default; opt in via options.isEnableStandaloneAppStartTracing = true or manifest meta-data io.sentry.standalone-app-start-tracing.enable
- Emits a transaction named App Start with op app.start, carrying the existing app start measurements and phase spans (process.load, contentprovider.load, application.load, activity lifecycle spans) as direct children of the root
- The standalone transaction shares the same traceId as the first ui.load activity transaction so they remain linked in the trace view
- Also covers non-activity starts (broadcast receivers, services, content providers)

Reduce boxing to improve performance (#5523, #5527, #5551)
Replace Date with a unix timestamp in SentryNanotimeDate to improve performance (#5550)
- SentryNanotimeDate is now marked @ApiStatus.Internal. A new (long unixDateMillis, long nanos) constructor was added, where unixDateMillis is milliseconds since the epoch. The existing (Date, long) constructor is retained but deprecated.

Fix attachments being duplicated on native events that carry scope attachments (#5548)
Fix performance collector scheduling many tasks in a row (#5524)