fix(preprod): Add organization_slug to snapshot log statements

[NicoHinderling]

Summary

• Adds organization_slug to 4 preprod snapshot log statements for easier filtering by organization in logging dashboards
• Replaces organization_id with organization_slug in the snapshot creation log
• Adds organization_slug to auto-approve, comparison complete, and comparison failed logs

doing this for our sentry dashboard usage

[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

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[sentry]

Bug: Accessing head_artifact in the generic exception handler can cause a NameError if it was never assigned, masking the original error.
_{Severity: MEDIUM}

Suggested Fix

Initialize head_artifact to None before the try block. In the exception handler, conditionally access head_artifact.project.organization.slug only if head_artifact is not None to prevent the NameError.

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/preprod/snapshots/tasks.py#L742

Potential issue: In the outer `except BaseException:` block, the code accesses
`head_artifact` to log the organization slug. However, if an exception other than
`PreprodArtifact.DoesNotExist` (such as a `DatabaseError` or `TimeoutError`) occurs when
initially fetching `head_artifact`, the variable will not be defined. This will cause a
`NameError` inside the exception handler, which masks the original, more informative
exception and prevents proper error logging and debugging.

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