Gauge: Fixes issue with all null values cause min & max to be null (#30156)

e2e/suite1/specs/gauge.spec.ts

@@ -0,0 +1,24 @@
+import { e2e } from '@grafana/e2e';
+
+e2e.scenario({
+  describeName: 'Gauge Panel',
+  itName: 'Gauge rendering e2e tests',
+  addScenarioDataSource: false,
+  addScenarioDashBoard: false,
+  skipScenario: false,
+  scenario: () => {
+    // open Panel Tests - Gauge
+    e2e.flows.openDashboard({ uid: '_5rDmaQiz' });
+
+    cy.wait(1000);
+
+    // check that gauges are rendered
+    e2e()
+      .get('body')
+      .find(`.flot-base`)
+      .should('have.length', 16);
+
+    // check that no panel errors exist
+    e2e.components.Panels.Panel.headerCornerInfo('error').should('not.exist');
+  },
+});