feat: Migrates the geocoding-region-es sample to js-api-samples.

[willum070]

This PR does the following things:

• Migrates the geocoding-region-es sample to js-api-samples.
• Refactors the map to use the gmp-map element and dynamic library loading.
• Replaces legacy dynamic map markers instantiation assignment format to use google.maps.marker.AdvancedMarkerElement.
• Cleans up overall layout rules and global types annotations definitions.

[snippet-bot]

Here is the summary of changes.

You are about to add 3 region tags.

• samples/geocoding-region-es/index.html:7, tag maps_js_geocoding_region_es
• samples/geocoding-region-es/index.ts:9, tag maps_js_geocoding_region_es
• samples/geocoding-region-es/style.css:6, tag maps_js_geocoding_region_es

---

This comment is generated by snippet-bot.
If you find problems with this result, please file an issue at:
https://github.com/googleapis/repo-automation-bots/issues.
To update this comment, add snippet-bot:force-run label or use the checkbox below:

• Refresh this comment