Deprecated `enable_tracing` option in Python SDK docs.

### SDK

Python SDK

### Description

We deprecated the `enable_tracing` option in the Python SDK here: https://github.com/getsentry/sentry-python/pull/3935



### Suggested Solution

- Remove all usages of `enable_tracing` from the Python SDK docs code snippets.
- Add a `deprecated` marker (including the version it was deprecated in) to the options description itself. 