Fix NGF grafana for new metrics (#584)

Problem: Agent metrics were updated, but the NGF sample dashboard was not.

Solution: Update the dashboard with the new metrics name.

Author: sjberman

static/ngf/ngf-grafana-dashboard.json

@@ -339,7 +339,7 @@
           "disableTextWrap": false,
           "editorMode": "builder",
           "exemplar": false,
-          "expr": "irate(nginx_http_connections_count{instance=~\"$nginx_instance\", nginx_connections_outcome=\"ACTIVE\"}[1m])",
+          "expr": "irate(nginx_http_connection_count_connections{instance=~\"$nginx_instance\", nginx_connections_outcome=\"ACTIVE\"}[1m])",
           "fullMetaSearch": false,
           "includeNullMetadata": true,
           "instant": false,
@@ -355,7 +355,7 @@
           },
           "disableTextWrap": false,
           "editorMode": "builder",
-          "expr": "irate(nginx_http_connections_count{instance=~\"$nginx_instance\", nginx_connections_outcome=\"READING\"}[1m])",
+          "expr": "irate(nginx_http_connection_count_connections{instance=~\"$nginx_instance\", nginx_connections_outcome=\"READING\"}[1m])",
           "fullMetaSearch": false,
           "hide": false,
           "includeNullMetadata": true,
@@ -372,7 +372,7 @@
           },
           "disableTextWrap": false,
           "editorMode": "builder",
-          "expr": "irate(nginx_http_connections_count{instance=~\"$nginx_instance\", nginx_connections_outcome=\"WAITING\"}[1m])",
+          "expr": "irate(nginx_http_connection_count_connections{instance=~\"$nginx_instance\", nginx_connections_outcome=\"WAITING\"}[1m])",
           "fullMetaSearch": false,
           "hide": false,
           "includeNullMetadata": true,
@@ -389,7 +389,7 @@
           },
           "disableTextWrap": false,
           "editorMode": "builder",
-          "expr": "irate(nginx_http_connections_count{instance=~\"$nginx_instance\", nginx_connections_outcome=\"WRITING\"}[1m])",
+          "expr": "irate(nginx_http_connection_count_connections{instance=~\"$nginx_instance\", nginx_connections_outcome=\"WRITING\"}[1m])",
           "fullMetaSearch": false,
           "hide": false,
           "includeNullMetadata": true,