Pyroscope: Remove support for old pyroscope (#74683)

pkg/tests/api/plugins/data/expectedListResp.json

@@ -671,7 +671,7 @@
         "name": "Grafana Labs",
         "url": "https://www.grafana.com"
       },
-      "description": "Supports Phlare and Pyroscope backends, horizontally-scalable, highly-available, multi-tenant continuous profiling aggregation systems.",
+      "description": "Data source for Grafana Pyroscope, horizontally-scalable, highly-available, multi-tenant continuous profiling aggregation system.",
       "links": [
         {
           "name": "GitHub Project",
@@ -1896,4 +1896,4 @@
     "signatureOrg": "",
     "angularDetected": false
   }
-]
+]