patch 8.2.3557: Vim9: cannot call imported funcref at script level

Problem:    Vim9: cannot call imported funcref at script level.
Solution:   Check for an imported function. (closes #9007)
diff --git a/src/version.c b/src/version.c
index 362129e..ea396cd 100644
--- a/src/version.c
+++ b/src/version.c
@@ -758,6 +758,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    3557,
+/**/
     3556,
 /**/
     3555,