I18N: Make the minimum input length to start searching posts in the "Insert/edit link" modal localizable.

Props Toro_Unit, birgire, miyauchi, swissspidy, ocean90.
Fixes #44662.

git-svn-id: https://develop.svn.wordpress.org/trunk@46988 602fd350-edb4-49c9-b593-d223f7449a82

src/js/_enqueues/lib/link.js

@@ -507,9 +507,10 @@
 
 		searchInternalLinks: function() {
 			var waiting,
-				search = inputs.search.val() || '';
+				search = inputs.search.val() || '',
+				minInputLength = parseInt( wpLinkL10n.minInputLength, 10 ) || 3;
 
-			if ( search.length > 2 ) {
+			if ( search.length >= minInputLength ) {
 				rivers.recent.hide();
 				rivers.search.show();