log_item, log_byte & trace_metric_byte Support

### Description

Emit `log_item`, `log_byte`, and `trace_metric_byte` client outcomes and handle all relevant categories in rate limiting.

### User-facing changes

After this ships, the .NET SDK will:
- emit log_item client outcomes when dropping logs
- emit log_byte client outcomes when dropping logs
- emit trace_metric_byte client outcomes when dropping metrics
- respect incoming rate limits for log_item, log_byte, and trace_metric_byte

### In scope

- Client outcomes: emit log_item and log_byte when dropping logs and trace_metric_byte when dropping metrics
- Rate limiting: handle incoming rate limit responses for log_item, log_byte, and trace_metric_byte

### Definition of Done

- [ ] .NET emits log_item outcomes for log drops
- [ ] .NET emits log_byte outcomes for log drops
- [ ] .NET emits trace_metric_byte outcomes for metric drops
- [ ] .NET respects rate limits for log_item
- [ ] .NET respects rate limits for log_byte
- [ ] .NET respects rate limits for trace_metric_byte
- [ ] behavior is covered by tests where appropriate

### Additional References

- https://develop.sentry.dev/sdk/foundations/transport/rate-limiting/
- https://develop.sentry.dev/sdk/telemetry/client-reports/#metric-byte-outcomes
- https://develop.sentry.dev/sdk/telemetry/client-reports/#log-byte-outcomes

Start by locating the .NET SDK's client-outcome emission and rate-limiting handling, then read the linked rate-limiting and telemetry references. Add coverage for log_item, log_byte, and trace_metric_byte drops and incoming limits; done means all six Definition of Done checks pass.

Written by the indexing model from the issue text.