[Issue Stream] Add runtime context to group details

[s1gr1d]

In PR #88312, runtime labels for JS Errors were added. Those "Frontend" and "Backend" labels should also be added to issue stream items like this (only JS SDK issues):

In the event details, this runtime context information is retrieved from the already existing event details. In the issue stream, this runtime information is not available, as the backend returns grouped issues.

Develop Docs: Runtime Context

Including the runtime context issue stream probably requires the following changes:

• Changing the issues endpoint: OrganizationGroupIndexEndpoint
• Including runtime to the data here (is returned in the issues endpoint):

  sentry/src/sentry/models/group.py

  Lines 598 to 600 in af33c2a

  	data: models.Field[dict[str, Any] | None, dict[str, Any]] = GzippedDictField(
  	blank=True, null=True
  	)

• Getting the runtime on Relay and adding it to the data dict mentioned above.

related to #85732