[Bug]: page generator does not work on standalone applications

[vscaiceanu-1a]

Package name

core, schematics

Package version

10.3.6

Reproduction steps

npm create @o3r otter-project
cd otter-project
ng g application webapp
# choose preset BASIC, NO Jest and NO Playwright when prompted
ng g page my-page
? Application routing module path? ./src/app/app-routing.module.ts
Generate component with Otter fixture? Yes
Generate future components with useComponentFixtures by default? Yes, always

Current result

    Cannot read ./src/app/app-routing.module.ts
    No Routes declaration found
CREATE apps/webapp/src/app/my-page/my-page.module.ts (425 bytes)
CREATE apps/webapp/src/app/my-page/my-page.component.ts (417 bytes)
CREATE apps/webapp/src/app/my-page/my-page.spec.ts (890 bytes)
CREATE apps/webapp/src/app/my-page/my-page.style.scss (0 bytes)
CREATE apps/webapp/src/app/my-page/my-page.template.html (22 bytes)
CREATE apps/webapp/src/app/my-page/README.md (36 bytes)
CREATE apps/webapp/src/app/my-page/index.ts (34 bytes)
CREATE apps/webapp/src/app/my-page/my-page.fixture.ts (104 bytes)
UPDATE angular.json (4454 bytes)

Expected result

No errors and routing correctly handled.

Additional comments

Coming from page schematics:

packages/@o3r/schematics/src/utility/routes.ts and packages/@o3r/core/schematics/page/index.ts