patch 8.2.3249: Vim9: error for re-imported function with default argument

Problem:    Vim9: error for re-imported function with default argument.
Solution:   Do not check argument type if it is still unknown. (closes #8653)
diff --git a/src/vim9script.c b/src/vim9script.c
index 641b0dd..40f857f 100644
--- a/src/vim9script.c
+++ b/src/vim9script.c
@@ -623,9 +623,10 @@
 		    && (imported->imp_flags & IMP_FLAGS_RELOAD)
 		    && imported->imp_sid == sid
 		    && (idx >= 0
-			? (equal_type(imported->imp_type, type)
+			? (equal_type(imported->imp_type, type, 0)
 			    && imported->imp_var_vals_idx == idx)
-			: (equal_type(imported->imp_type, ufunc->uf_func_type)
+			: (equal_type(imported->imp_type, ufunc->uf_func_type,
+							     ETYPE_ARG_UNKNOWN)
 			    && STRCMP(imported->imp_funcname,
 							ufunc->uf_name) == 0)))
 	    {