If ehpa is configured with prediction but does not contain predictable metrics, then no tsp object is created

[whitebear009]

What type of PR is this?

bugfix

What this PR does / why we need it:

If ehpa is configured with prediction but does not contain predictable metrics, ehpa conotroller will throw error like below:

E0531 17:15:57.094143 1 predict.go:71] Failed to create TimeSeriesPrediction khrd-geom-middleware-prod/ehpa-kigma-render-service-prod-hpa-preview error admission webhook "vprediction.crane.io" denied the request: PredictionMetrics is null
So we need to add a judgment condition, in this case, no tsp object is created.

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

[github-actions]

🎉 Successfully Build Images.

Overview: https://finops.coding.net/public-artifacts/gocrane/crane/packages

Image	Pull Command
crane-agent:pr-340-a160190	docker pull finops-docker.pkg.coding.net/gocrane/crane/crane-agent:pr-340-a160190
dashboard:pr-340-a160190	docker pull finops-docker.pkg.coding.net/gocrane/crane/dashboard:pr-340-a160190
metric-adapter:pr-340-a160190	docker pull finops-docker.pkg.coding.net/gocrane/crane/metric-adapter:pr-340-a160190
craned:pr-340-a160190	docker pull finops-docker.pkg.coding.net/gocrane/crane/craned:pr-340-a160190

[qmhu]

/LGTM