patch 8.2.1612: Vim9: cannot pass "true" to prop_remove()

Problem:    Vim9: cannot pass "true" to prop_remove().
Solution:   Use dict_get_bool(). (closes #6853)
diff --git a/src/version.c b/src/version.c
index bcece94..34516ac 100644
--- a/src/version.c
+++ b/src/version.c
@@ -755,6 +755,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1612,
+/**/
     1611,
 /**/
     1610,