GraphNG: accept number for spanNulls to indicate max threshold below which nulls are connected (#32146)

devenv/dev-dashboards/panel-graph/graph-ng-nulls.json

@@ -1026,6 +1026,104 @@
       "title": "Null values in second series show gaps (bugged)",
       "transformations": [],
       "type": "timeseries"
+    },
+    {
+      "datasource": null,
+      "fieldConfig": {
+        "defaults": {
+          "color": {
+            "mode": "palette-classic"
+          },
+          "custom": {
+            "axisLabel": "",
+            "axisPlacement": "auto",
+            "barAlignment": 0,
+            "drawStyle": "line",
+            "fillOpacity": 10,
+            "gradientMode": "none",
+            "hideFrom": {
+              "graph": false,
+              "legend": false,
+              "tooltip": false
+            },
+            "lineInterpolation": "linear",
+            "lineWidth": 1,
+            "pointSize": 5,
+            "scaleDistribution": {
+              "type": "linear"
+            },
+            "showPoints": "never",
+            "spanNulls": 3600000
+          },
+          "mappings": [],
+          "thresholds": {
+            "mode": "absolute",
+            "steps": [
+              {
+                "color": "green",
+                "value": null
+              },
+              {
+                "color": "red",
+                "value": 80
+              }
+            ]
+          },
+          "unit": "short"
+        },
+        "overrides": []
+      },
+      "gridPos": {
+        "h": 8,
+        "w": 10,
+        "x": 14,
+        "y": 14
+      },
+      "id": 13,
+      "options": {
+        "graph": {},
+        "legend": {
+          "calcs": [],
+          "displayMode": "list",
+          "placement": "bottom"
+        },
+        "tooltipOptions": {
+          "mode": "single"
+        }
+      },
+      "pluginVersion": "7.5.0-pre",
+      "targets": [
+        {
+          "alias": "",
+          "csvWave": {
+            "timeStep": 60,
+            "valuesCSV": "0,0,2,2,1,1"
+          },
+          "lines": 10,
+          "points": [],
+          "pulseWave": {
+            "offCount": 3,
+            "offValue": 1,
+            "onCount": 3,
+            "onValue": 2,
+            "timeStep": 60
+          },
+          "refId": "A",
+          "scenarioId": "csv_metric_values",
+          "stream": {
+            "bands": 1,
+            "noise": 2.2,
+            "speed": 250,
+            "spread": 3.5,
+            "type": "signal"
+          },
+          "stringInput": "1,20,90,null,30,5,0"
+        }
+      ],
+      "timeFrom": null,
+      "timeShift": null,
+      "title": "Span nulls below 1hr",
+      "type": "timeseries"
     }
   ],
   "schemaVersion": 27,