#7205109 DIFM: Use new page IDs in the Website Content step

Changes proposed in this Pull Request

There are a few related changes in this PR for the Website Content step of the DIFM flow. This PR adds some groundwork to make future changes easier. The next change is to add more text fields to the Contact page section of this step.

• Use the new page IDs introduced in #61790.
• Add MENU_PAGE and SERVICE_PAGE as constants. These don’t need to be added to the page-picker component, however.
• Modify useTranslatedPageTitles to return all translated page titles instead for a particular page id. This makes the hook easier to use and we avoid calling the hook multiple times in client/signup/steps/website-content/index.tsx.
• Also added useMemo to useTranslatedPageTitles so that the translate function is not executed every time this hook is executed.

Testing instructions

• Go to /start/do-it-for-me.
• After checkout, on the Website Content step, confirm that all the page titles are displayed correctly.