@grafana/e2e: fix dependencies (#24109)

* @cypress/webpack-preprocessor is needed at runtime

* Removed redundant packages

* Removed unnecessary packages

(cherry picked from commit b027e25127)

packages/grafana-e2e/package.json

@@ -30,7 +30,6 @@
     "typecheck": "tsc --noEmit"
   },
   "devDependencies": {
-    "@cypress/webpack-preprocessor": "4.1.3",
     "@rollup/plugin-commonjs": "11.0.2",
     "@rollup/plugin-node-resolve": "7.1.1",
     "@types/node": "13.7.7",
@@ -40,12 +39,11 @@
     "rollup-plugin-sourcemaps": "0.5.0",
     "rollup-plugin-terser": "5.3.0",
     "rollup-plugin-typescript2": "0.26.0",
-    "rollup-plugin-visualizer": "3.3.1",
-    "ts-loader": "6.2.1",
-    "ts-node": "8.8.1"
+    "rollup-plugin-visualizer": "3.3.1"
   },
   "types": "src/index.ts",
   "dependencies": {
+    "@cypress/webpack-preprocessor": "4.1.3",
     "@grafana/e2e-selectors": "7.0.0-beta.1",
     "@grafana/tsconfig": "^1.0.0-rc1",
     "blink-diff": "1.0.13",