Remove setting init.userspace_reboot.is_supported

Userspace reboot is deprecated.

Bug: 292469129
Test: build cuttlefish.
Test: adb shell getprop init.userspace_reboot.is_supported
Change-Id: I51ded79d3ae3df5363e6a7c9d1c5dcd06163f78e
diff --git a/target/product/userspace_reboot.mk b/target/product/userspace_reboot.mk
index f235d14..51feb07 100644
--- a/target/product/userspace_reboot.mk
+++ b/target/product/userspace_reboot.mk
@@ -14,6 +14,4 @@
 # limitations under the License.
 #
 
-# Inherit this when the target supports userspace reboot
-
-PRODUCT_VENDOR_PROPERTIES := init.userspace_reboot.is_supported=true
+# DEPRECATED! Do not inherit this.