uls.lcd: Add auto-correcting code when index goes beyond max index

Leave the error logging code in place in order to identify any
other places where this issue occurs.

Bug: https://phabricator.wikimedia.org/T328956

src/jquery.uls.lcd.js

@@ -112,8 +112,15 @@
 			if ( this.navigationIndex === null ) {
 				this.navigationIndex = 0;
 			} else {
-				this.navigationIndex++;
+				// Auto-correct the index. It has been noticed that the navigationIndex goes beyond the
+				// max index sometimes. See: phab:T328956#8854835
+				if ( this.navigationIndex > maxIndex ) {
+					this.navigationIndex = maxIndex;
+				} else {
+					this.navigationIndex++;
+				}
 			}
+
 			this.highlightLanguageOption();
 		},