Build: Optional skipping of typescript checking in dev bundler (#18772)

* Build: Removed typescript checking from dev bundler

- when switching branches and trying out features, TS checking and bundling are eating up a lot
of CPU
- most of us are using an editor with typechecking support
- this commit removes type checking from the dev bundler
- we still have type checking enabled as a precommit hook and as part of
the prod bundler

* Adds new npm script: start:noTsCheck

scripts/webpack/webpack.prod.js

@@ -5,6 +5,7 @@ const TerserPlugin = require('terser-webpack-plugin');
 const common = require('./webpack.common.js');
 const path = require('path');
 const ngAnnotatePlugin = require('ng-annotate-webpack-plugin');
+const ForkTsCheckerWebpackPlugin = require('fork-ts-checker-webpack-plugin');
 const HtmlWebpackPlugin = require("html-webpack-plugin");
 const MiniCssExtractPlugin = require("mini-css-extract-plugin");
 const OptimizeCSSAssetsPlugin = require("optimize-css-assets-webpack-plugin");
@@ -58,6 +59,9 @@ module.exports = merge(common, {
     ]
   },
   plugins: [
+    new ForkTsCheckerWebpackPlugin({
+      checkSyntacticErrors: true,
+    }),
     new MiniCssExtractPlugin({
       filename: "grafana.[name].[hash].css"
     }),