Sentry before_send/transport dotted-path config never resolved to a callable in Task SDK (silently drops all events)

### Under which category would you file this issue?

Task SDK

### Apache Airflow version

3.2.2 (also reproduced, unchanged, on 3.3.0rc2)

### What happened and how to reproduce it?

When `[sentry] before_send` (e.g. `AIRFLOW__SENTRY__BEFORE_SEND=`) is configured,
`ConfiguredSentry.prepare_to_enrich_errors()` in
`task-sdk/src/airflow/sdk/execution_time/sentry/configured.py` never resolves it into an
actual callable — it gets passed to `sentry_sdk.init()` as the raw string:

```python
sentry_config_opts: dict[str, Any] = conf.getsection("sentry") or {}
if sentry_config_opts:
sentry_config_opts.pop("sentry_on")
old_way_dsn = sentry_config_opts.pop("sentry_dsn", None)
new_way_dsn = sentry_config_opts.pop("dsn", None)
dsn = old_way_dsn or new_way_dsn
...
else:
dsn = None
if before_send := conf.getimport("sentry", "before_send", fallback=None):
sentry_config_opts["before_send"] = before_send
if transport := conf.getimport("sentry", "transport", fallback=None):
sentry_config_opts["transport"] = transport

if dsn:
sentry_sdk.init(dsn=dsn, integrations=integrations, **sentry_config_opts)
```

`conf.getsection("sentry")` always returns a non-empty dict — it starts from the section's
schema defaults (`sentry_on`, `sentry_dsn` both have non-None defaults) — so the
`if sentry_config_opts:` branch is *always* taken, and the `else` branch (the only place
`before_send`/`transport` get resolved via `conf.getimport()`) is unreachable dead code.

As a result, `sentry_sdk.init(before_send="my.dotted.path", ...)` receives a plain string.
At event-capture time, `sentry_sdk`'s `Client._prepare_event` calls `before_send(event, hint)`,
raising `TypeError: 'str' object is not callable`. This is swallowed internally by
`capture_internal_exceptions()` (logged only via the internal `sentry_sdk.errors` logger) —
the event is silently dropped with no error surfaced and nothing delivered to Sentry.
Same issue applies to `transport`.

This is a regression from Airflow 2.x's `airflow/sentry.py`, where the equivalent
`conf.getimport(...)` calls ran unconditionally:

```python
sentry_config_opts["before_send"] = conf.getimport("sentry", "before_send", fallback=None)
sentry_config_opts["transport"] = conf.getimport("sentry", "transport", fallback=None)
```

(see 2.11.0's `airflow/sentry.py`). This logic appears to have been ported into the Task SDK
reimplementation in #57032, but the branching structure changed such that the resolution
path became unreachable.

**Steps to reproduce:**

```
AIRFLOW__SENTRY__SENTRY_ON=True
AIRFLOW__SENTRY__SENTRY_DSN=
AIRFLOW__SENTRY__BEFORE_SEND=path.to.a.real.before_send.function
```

```python
from airflow.sdk.execution_time.sentry.configured import ConfiguredSentry
cs = ConfiguredSentry()
cs.prepare_to_enrich_errors(executor_integration="")
import sentry_sdk
print(type(sentry_sdk.get_client().options.get("before_send")))
# prints instead of the resolved function
```

Any subsequent `sentry_sdk.capture_exception()` / `capture_message()` call will silently
fail to deliver its event.

### What you think should happen instead?

`before_send`/`transport` dotted paths configured via `[sentry]` should always be resolved
into real callables via `conf.getimport()`, regardless of what else is set in the `[sentry]`
section — matching 2.x behavior, e.g.:

```python
sentry_config_opts: dict[str, Any] = conf.getsection("sentry") or {}
sentry_config_opts.pop("sentry_on", None)
old_way_dsn = sentry_config_opts.pop("sentry_dsn", None)
new_way_dsn = sentry_config_opts.pop("dsn", None)
dsn = old_way_dsn or new_way_dsn
if before_send := conf.getimport("sentry", "before_send", fallback=None):
sentry_config_opts["before_send"] = before_send
if transport := conf.getimport("sentry", "transport", fallback=None):
sentry_config_opts["transport"] = transport
```

### Operating System

N/A — reproduced via the official `apache/airflow:3.2.2-python3.12` and
`apache/airflow:3.3.0rc2-python3.12` images.

### Deployment

Other Docker-based deployment

### Apache Airflow Provider(s)

_No response_

### Versions of Apache Airflow Providers

_No response_

### Official Helm Chart version

Not Applicable

### Kubernetes Version

Not Applicable

### Helm Chart configuration

Not Applicable

### Docker Image customizations

Not Applicable — reproduced against the unmodified official images.

### Anything else?

This is separate from #52368 / #65136 / #65161 (uncaught task exceptions not captured by
Sentry), which is fixed in 3.3.0. This `before_send`/`transport` resolution bug is a
different issue, still present unchanged in 3.3.0rc2.

### Are you willing to submit PR?

- [ ] Yes I am willing to submit a PR!

### Code of Conduct

- [x] I agree to follow this project's Code of Conduct

Start in task-sdk/src/airflow/sdk/execution_time/sentry/configured.py, specifically ConfiguredSentry.prepare_to_enrich_errors(), and compare its [sentry] option handling with the 2.11.0 airflow/sentry.py behavior described in the issue. Verify the configured before_send and transport values are resolved through conf.getimport() before sentry_sdk.init() receives them. Done means dotted paths become callable options even when the Sentry section has schema defaults, without dropping events.

Written by the indexing model from the issue text.