[core][autoscalerV2] Strucutred cluster_status endpoint

[rickyyx]

What happened + What you expected to happen

for /api/cluster_status, we should not be returning (un)format strings to the client, but a structured output for maintainability.

ray/dashboard/modules/reporter/reporter_head.py

Lines 95 to 108 in 6606cc8

	async def get_cluster_status(self, req):
	"""Returns status information about the cluster.
	Currently contains two fields:
	autoscaling_status (str)-- a status message from the autoscaler.
	autoscaling_error (str)-- an error message from the autoscaler if
	anything has gone wrong during autoscaling.
	These fields are both read from the GCS, it's expected that the
	autoscaler writes them there.
	"""
	# TODO(rickyx): We should be able to get the cluster status from the
	# autoscaler directly with V2. And we should be able to return structured data
	# rather than a string.

Versions / Dependencies

master

Reproduction script

NA

Issue Severity

None