fix: cleanup playwright templates from o3r/core (#1634)

## Proposed change

Playwright templates are now in `@o3r/testing`s `ng-add`. However, there
are some leftover templates for playwright in `@o3r/core`.
The goal is to clean them up.

packages/@o3r/core/schematics/rule-factories/index.ts

@@ -2,5 +2,4 @@ export * from './o3r-basic-updates/index';
 export * from './additional-modules/index';
 export * from './customization-environment/index';
 export * from './otter-environment/index';
-export * from './playwright/index';
 export * from './store/index';