Add GA custom event for Internal navigation to DOM elements

[nozomione]

Context

Epic: #302

We need to collect data for internal links in GA reports.

Google sheet Custom events: Internal Link

Problem or idea

We should add GA4 custom events for internal links to DOM elements GA4 custom event script.

Solution or next step

• Add custom events for internal links to DOM elements using the GA custom events script
• Verify that custom events are firing correctly in the development environment