Update dialplans.php (#4606)

removing potential for Warning: sizeof(): Parameter must be an array or an object that implements Countable

app/dialplans/dialplans.php

@@ -446,6 +446,7 @@
 	}
 	echo "<br><br>";
 
+	if (is_array($dialplans)) {
 		if (sizeof($dialplan_ids) > 0) {
 			echo "<script>\n";
 			echo "	function check(what) {\n";
@@ -456,7 +457,7 @@
 			echo "	}\n";
 			echo "</script>\n";
 		}
-
+	}
 //include the footer
 	require_once "resources/footer.php";