[Maps] Improve language for mvt card (#71947) (#74081)

This reduces ambiguity about the source type.

Author: thomasneirynck

x-pack/plugins/maps/public/classes/sources/mvt_single_layer_vector_source/__snapshots__/mvt_single_layer_source_settings.test.tsx.snap

@@ -133,7 +133,7 @@ export class MVTSingleLayerSourceSettings extends Component<Props, State> {
           label={i18n.translate(
             'xpack.maps.source.MVTSingleLayerVectorSourceEditor.layerNameMessage',
             {
-              defaultMessage: 'Tile layer',
+              defaultMessage: 'Source layer',
             }
           )}
         >

x-pack/plugins/maps/public/classes/sources/mvt_single_layer_vector_source/mvt_single_layer_source_settings.tsx

@@ -84,7 +84,7 @@ describe('getImmutableSourceProperties', () => {
     const source = new MVTSingleLayerVectorSource(descriptor);
     const properties = await source.getImmutableProperties();
     expect(properties).toEqual([
-      { label: 'Data source', value: '.pbf vector tiles' },
+      { label: 'Data source', value: 'Vector tiles' },
       { label: 'Url', value: 'https://example.com/{x}/{y}/{z}.pbf' },
     ]);
   });

x-pack/plugins/maps/public/classes/sources/mvt_single_layer_vector_source/mvt_single_layer_vector_source.test.tsx

@@ -32,7 +32,7 @@ import { ITooltipProperty, TooltipProperty } from '../../tooltips/tooltip_proper
 export const sourceTitle = i18n.translate(
   'xpack.maps.source.MVTSingleLayerVectorSource.sourceTitle',
   {
-    defaultMessage: '.pbf vector tiles',
+    defaultMessage: 'Vector tiles',
   }
 );