Enforce min_sdk_version=30

These tests are run as part of the MTS suite, setting min_sdk_version
ensures that these tests can be installed on an older device and test
the corresponding mainline module.

Test: atest [<mod_name>...]
Bug: 156476221
Change-Id: Ic94b00ee1818063fc9f13e4ecffaca88f58c30c3
diff --git a/Tethering/tests/privileged/Android.bp b/Tethering/tests/privileged/Android.bp
index ba6be66..3597a91 100644
--- a/Tethering/tests/privileged/Android.bp
+++ b/Tethering/tests/privileged/Android.bp
@@ -53,4 +53,5 @@
         "TetheringApiCurrentLib",
     ],
     compile_multilib: "both",
+    min_sdk_version: "30",
 }