Do not fail on input completion when source is an Array

Closes #13088
(grafted from 0d99c0394ebc50547cd18570833e68d908791300)

--HG--
branch : 6.0

sao/src/common.js

@@ -3617,7 +3617,7 @@
             }
             var prm;
             if (this.source instanceof Array) {
-                prm = jQuery.when(source.filter(function(value) {
+                prm = jQuery.when(this.source.filter(function(value) {
                     return value.toLowerCase().startsWith(text.toLowerCase());
                 }));
             } else {