chore(grafana-ui): bump storybook to 6.1.15 (#30642)

packages/grafana-ui/package.json

@@ -78,12 +78,12 @@
     "@rollup/plugin-commonjs": "16.0.0",
     "@rollup/plugin-image": "2.0.5",
     "@rollup/plugin-node-resolve": "10.0.0",
-    "@storybook/addon-controls": "6.1.9",
-    "@storybook/addon-essentials": "6.1.9",
-    "@storybook/addon-knobs": "6.1.9",
-    "@storybook/addon-storysource": "6.1.9",
-    "@storybook/react": "6.1.9",
-    "@storybook/theming": "6.1.9",
+    "@storybook/addon-controls": "6.1.15",
+    "@storybook/addon-essentials": "6.1.15",
+    "@storybook/addon-knobs": "6.1.15",
+    "@storybook/addon-storysource": "6.1.15",
+    "@storybook/react": "6.1.15",
+    "@storybook/theming": "6.1.15",
     "@types/classnames": "2.2.7",
     "@types/common-tags": "^1.8.0",
     "@types/d3": "5.7.2",
@@ -110,7 +110,7 @@
     "rollup-plugin-terser": "7.0.2",
     "rollup-plugin-typescript2": "0.29.0",
     "rollup-plugin-visualizer": "4.2.0",
-    "storybook-dark-mode": "1.0.3",
+    "storybook-dark-mode": "1.0.4",
     "ts-loader": "8.0.11",
     "typescript": "4.1.2",
     "webpack-filter-warnings-plugin": "1.2.1"