feat(cells) Make organization avatar URL cell compatible

[markstory]

I was reviewing the URL exception list and saw that this URL needed an org scoped endpoint added. I've added a new URL path for that includes the organization's slug, and moved the URL generation into model methods so that the absolute_url() interface from BaseAvatar is provided by both the cell + control models.

Refs INFRENG-319

[linear-code]

INFRENG-319

[cursor]

Cursor Bugbot has reviewed your changes and found 2 potential issues.

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[strongs]

nitpick: I think we can remove this attribute, looks like OrganizationAvatar.absolute_url uses reverse(), and never reads this attribute, and likewise AvatarBase.absolute_url does read this but it gets overridden here

[sentry-warden]

OrganizationAvatarReplica.absolute_url() raises DoesNotExist if OrganizationMapping is missing

Calling avatar_replica.absolute_url() in the serializer will propagate an unhandled OrganizationMapping.DoesNotExist if the mapping row hasn't been replicated yet or was deleted, crashing the endpoint — wrap the call in a try/except or fall back to None for avatarUrl.

Evidence

• avatar_replica.absolute_url() (in organizationavatarreplica.py, line 33) calls OrganizationMapping.objects.get_from_cache(organization_id=self.organization_id).
• get_from_cache ultimately calls .get(**kwargs) on a cache miss (confirmed in db/models/manager/base.py lines 314, 323).
• If the OrganizationMapping row does not exist, Django raises OrganizationMapping.DoesNotExist.
• Neither absolute_url() nor the serializer's serialize() method catches this exception.
• An OrganizationAvatarReplica can exist before its corresponding OrganizationMapping has been fully replicated across silos, making this a real race condition.

_{Identified by Warden sentry-backend-bugs · 7UC-E35}

[markstory]

If the mapping record is gone the org is too.

[sentry-warden]

OrganizationMapping.objects.get_from_cache() raises unhandled DoesNotExist in absolute_url

If the OrganizationMapping for this avatar's organization_id has been deleted or not yet created, get_from_cache raises OrganizationMapping.DoesNotExist, which propagates unhandled through the serializer and causes a 500.

Evidence

• get_from_cache in BaseManager (base.py:283) is a thin caching wrapper around self.get(**kwargs) — it does not catch DoesNotExist.
• absolute_url calls OrganizationMapping.objects.get_from_cache(organization_id=self.organization_id) with no try/except.
• The serializer (organization.py:387) calls avatar_replica.absolute_url() unconditionally when an OrganizationAvatarReplica exists.
• An org can have a replica row while its mapping is concurrently deleted or not yet replicated, triggering the exception during serialization.

_{Identified by Warden sentry-backend-bugs · HXD-U5J}

[sentry-warden]

Organization.objects.get_from_cache() in absolute_url() raises DoesNotExist if organization is deleted

If the organization has been deleted while its avatar still exists, Organization.objects.get_from_cache(id=self.organization_id) will raise Organization.DoesNotExist, crashing any serialization that calls absolute_url() (e.g. the organization serializer at lines 387 and 545).

Evidence

• absolute_url() calls Organization.objects.get_from_cache(id=self.organization_id) with no try/except.
• get_from_cache ultimately calls .get(**kwargs) (base.py line 344) which raises DoesNotExist when the record is absent.
• The serializer (organization.py lines 387, 545) calls avatar_replica.absolute_url() / attrs["avatar"].absolute_url() without guarding against this exception.
• OrganizationAvatar is a ReplicatedCellModel, so the avatar replica can outlive the organization if deletion is not perfectly ordered.

_{Identified by Warden sentry-backend-bugs · ENG-WHM}

[markstory]

If the org is gone so is the avatar.