fix(@schematics/angular): configure library sourceRoot to project root

This ensures that test discovery can properly discover test files across secondary entry points without needing path traversal.

Author: alan-agius4

packages/schematics/angular/library/index.ts

@@ -98,7 +98,9 @@ function addLibToWorkspaceFile(
     workspace.projects.add({
       name: projectName,
       root: projectRoot,
-      sourceRoot: `${projectRoot}/src`,
+      // TODO(alanagius): consider re-adding this when we move away from ng-packagr.
+      // sourceRoot: `${projectRoot}/src`,
+      sourceRoot: projectRoot,
       projectType: ProjectType.Library,
       prefix: options.prefix,
       targets: {

packages/schematics/angular/library/index_spec.ts

@@ -328,7 +328,7 @@ describe('Library Schematic', () => {
       project: 'foo',
     };
     tree = await schematicRunner.runSchematic('component', componentOptions, tree);
-    expect(tree.exists('/projects/foo/src/lib/comp/comp.ts')).toBe(true);
+    expect(tree.exists('/projects/foo/lib/comp/comp.ts')).toBe(true);
   });
 
   it(`should support creating scoped libraries`, async () => {