Stable way to get script path for split bundles (microsoft#12191)

For #10496
Use a less hacky way to get the path to the scripts to support split bundles.

Author: DonJayamanne

src/client/datascience/notebook/renderer.ts

@@ -15,8 +15,6 @@ export class NotebookOutputRenderer implements VSCNotebookOutputRenderer {
     private _preloads: Uri[] = [];
     constructor() {
         const renderersFolder = path.join(EXTENSION_ROOT_DIR, 'out', 'datascience-ui', 'renderers');
-        this._preloads.push(Uri.file(path.join(renderersFolder, 'pvscDummy.js')));
-        this._preloads.push(Uri.file(path.join(renderersFolder, 'main.js')));
         this._preloads.push(Uri.file(path.join(renderersFolder, 'renderers.js')));
     }
 

src/datascience-ui/renderers/index.tsx

@@ -4,16 +4,13 @@
 'use strict';
 
 // This must be on top, do not change. Required by webpack.
-// tslint:disable-next-line: no-var-requires no-require-imports
-// require('../common/main');
 declare let __webpack_public_path__: string;
+const getPublicPath = () => {
+    const currentDirname = (document.currentScript as HTMLScriptElement).src.replace(/[^/]+$/, '');
+    return new URL(currentDirname).toString();
+};
 
-// tslint:disable-next-line: no-any
-if ((window as any).__PVSC_Public_Path) {
-    // This variable tells Webpack to this as the root path used to request webpack bundles.
-    // tslint:disable-next-line: no-any
-    __webpack_public_path__ = (window as any).__PVSC_Public_Path;
-}
+__webpack_public_path__ = getPublicPath();
 // This must be on top, do not change. Required by webpack.
 
 import type { nbformat } from '@jupyterlab/coreutils';