[GMap] - Block first Map Location URL removal

[madalingorbanescu]

Currently, first location can be deleted and after doing that, the map won't work anymore.

More infos here: https://github.com/pixelgrade/rosa/issues/472

[georgeolaru]

Closing as stale. This GMap pins issue is 6+ years old with no further activity. If still relevant on v2.0.0, please open a fresh issue.