render background source labels as text, not html

modules/ui/panels/background.js

@@ -33,7 +33,7 @@ export function uiPanelBackground(context) {
 
         list
             .append('li')
-            .html(_currSourceName);
+            .text(_currSourceName);
 
         _metadataKeys.forEach(function(k) {
             // DigitalGlobe vintage is available in raster layers for now.

modules/ui/sections/background_list.js

@@ -202,7 +202,7 @@ export function uiSectionBackgroundList(context) {
 
         label
             .append('span')
-            .html(function(d) { return d.label(); });
+            .text(function(d) { return d.label(); });
 
         enter.filter(function(d) { return d.id === 'custom'; })
             .append('button')
@@ -225,7 +225,7 @@ export function uiSectionBackgroundList(context) {
                 .placement((localizer.textDirection() === 'rtl') ? 'right' : 'left')
             )
             .append('span')
-            .html('★');
+            .text('★');
 
         layerList
             .call(updateLayerSelections);