feat: Migrates the event-domListener sample to js-api-samples.

[willum070]

This PR does the following things:

• Migrates the event-domListener sample to js-api-samples.
• Refactors the sample to use the gmp-map element.
• Updates the sample to replace addDomListener (deprecated) with addEventListener.
• Remove unused CSS style.

[snippet-bot]

Here is the summary of changes.

You are about to add 3 region tags.

• samples/event-domListener/index.html:7, tag maps_event_domListener
• samples/event-domListener/index.ts:7, tag maps_event_domListener
• samples/event-domListener/style.css:6, tag maps_event_domListener

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