Update wording on depfile property error

Bug: 307824623
Test: Presubmits
Change-Id: I25919150d2ee2483099e7cb710330dc259d57e66
diff --git a/genrule/genrule_test.go b/genrule/genrule_test.go
index d13e976..fa0ee17 100644
--- a/genrule/genrule_test.go
+++ b/genrule/genrule_test.go
@@ -708,7 +708,7 @@
 				depfile: true,
 				cmd: "cat $(in) > $(out) && cat $(depfile)",
 			`,
-			err: "depfile: Deprecated to ensure the module type is convertible to Bazel",
+			err: "depfile: Deprecated because with genrule sandboxing, dependencies must be known before the action is run in order to add them to the sandbox",
 		},
 		{
 			name: `no error when module is allowlisted`,