Allow empty extension location for internal notebook contributions

No need to specify a fake location

src/vs/workbench/api/common/extHost.protocol.ts

@@ -669,7 +669,7 @@ export interface WebviewExtensionDescription {
 
 export interface NotebookExtensionDescription {
 	readonly id: ExtensionIdentifier;
-	readonly location: UriComponents;
+	readonly location: UriComponents | undefined;
 }
 
 export enum WebviewEditorCapabilities {

src/vs/workbench/contrib/interactive/browser/interactive.contribution.ts

@@ -164,7 +164,7 @@ export class InteractiveDocumentContribution extends Disposable implements IWork
 		};
 		this._register(notebookService.registerNotebookController('interactive', {
 			id: new ExtensionIdentifier('interactive.builtin'),
-			location: URI.parse('interactive://test')
+			location: undefined
 		}, controller));
 
 		const info = notebookService.getContributedNotebookType('interactive');

src/vs/workbench/contrib/notebook/browser/notebookServiceImpl.ts

@@ -689,7 +689,9 @@ export class NotebookService extends Disposable implements INotebookService {
 	getNotebookProviderResourceRoots(): URI[] {
 		const ret: URI[] = [];
 		this._notebookProviders.forEach(val => {
-			ret.push(URI.revive(val.extensionData.location));
+			if (val.extensionData.location) {
+				ret.push(URI.revive(val.extensionData.location));
+			}
 		});
 
 		return ret;