patch 8.2.1609: Vim9: test fails when build without +channel

Problem:    Vim9: test fails when build without +channel.
Solution:   Add check for +channel. (closes #6879)
diff --git a/src/version.c b/src/version.c
index e1cdba6..9216408 100644
--- a/src/version.c
+++ b/src/version.c
@@ -755,6 +755,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1609,
+/**/
     1608,
 /**/
     1607,