Description of problem:
Alert details page throws below error for Loki Log based alerts on Logging 5.8.0

{"error":"error extracting selectors from query: syntax error: unexpected GT, expecting CLOSE_PARENTHESIS: 1:62","errorType":"observatorium-api","status":"error"}

Version: Logging 5.8.0, OCP 4.14

$ oc get csv -n openshift-logging
NAME                     DISPLAY                     VERSION   REPLACES   PHASE
cluster-logging.v5.8.0   Red Hat OpenShift Logging   5.8.0                Succeeded
loki-operator.v5.8.0     Loki Operator               5.8.0                Succeeded
$ oc version
Client Version: 4.12.0-ec.5
Kustomize Version: v4.5.7
Server Version: 4.14.0-0.nightly-2023-09-17-080720
Kubernetes Version: v1.27.4+2c287eb

How reproducible: Always

Steps to Reproduce:
1) Forward Logs to default Loki
2) Create Alerting rule for any tenant (app/infra)
3) When Alert is firing, Click on alert and see Alert details page

Actual results: observatorium-api error on Alert Detail page

Expected results: Alert detail graph should be displayed

Image: registry.redhat.io/openshift-logging/lokistack-gateway-rhel9@sha256:a421513579dc295bb6dcdd0ee0ced742eba7164c722333159961f5abaca80f79

Screenshot attached.