feat(): Add periodic resolution task for sourcemap configuration detectors

[wedamija]

Resolves stale sourcemap detectors when no new failures arrive for 30 minutes.

[sentry]

Bug: The handler variable can be None if state.detector.detector_handler returns None, but it's used without a null check, which will cause an AttributeError.
_{Severity: HIGH}

Suggested Fix

Add a check to ensure handler is not None before attempting to access its methods. For example: handler = state.detector.detector_handler; if not handler: return.

Prompt for AI Agent

Review the code at the location below. A potential bug has been identified by an AI
agent.
Verify if this is a real issue. If it is, propose a fix; if not, explain why it's not
valid.

Location: src/sentry/processing_errors/tasks.py#L71-L74

Potential issue: The `detector_handler` property can return `None` under certain
conditions, such as registry corruption or version mismatches during deployment. The
code in `_resolve_detector` retrieves this handler but then attempts to call methods on
it (`build_issue_fingerprint`, `build_key`) without first checking if the handler is
`None`. This will lead to an `AttributeError`, crashing the periodic task responsible
for sourcemap detector resolution. Other parts of the codebase correctly handle this
`None` case by performing a check before using the handler.

_{Did we get this right? 👍 / 👎 to inform future reviews.}