metadataPanel.formatDate: Account for timezoneness

As MDN says, new Date( dateString ) is strongly discouraged, for
exactly this reason. Oy.

Bug: T243160
Change-Id: Ib71b16185f5bd1cd522535716b6e36d2699678cd

resources/mmv/ui/mmv.ui.metadataPanel.js

@@ -816,7 +816,8 @@
 				return date.toLocaleString( lang, {
 					day: 'numeric',
 					month: 'long',
-					year: 'numeric'
+					year: 'numeric',
+					timeZone: 'UTC'
 				} );
 			}
 		} catch ( ignore ) {}