use existing spec for migrations job

deploy/charts/litellm-helm/templates/migrations-job.yaml

@@ -17,11 +17,12 @@ spec:
           command: ["python", "litellm/proxy/prisma_migration.py"]
           workingDir: "/app"
           env:
+            {{- if .Values.db.deployStandalone }}
             - name: DATABASE_URL
-              valueFrom:
-                secretKeyRef:
-                  name: db-secret
-                  key: DATABASE_URL
+              value: postgresql://{{ .Values.postgresql.auth.username }}:{{ .Values.postgresql.auth.password }}@{{ .Release.Name }}-postgresql/{{ .Values.postgresql.auth.database }}
+            {{- else if .Values.db.useExisting }}
+            - name: DATABASE_URL
+              value: {{ .Values.db.url | quote }}
             - name: DISABLE_SCHEMA_UPDATE
               value: "false" # always run the migration from the Helm PreSync hook, override the value set
       restartPolicy: OnFailure