Remove platform cert from Tethering tests

Bug: 156866746
Test: atest TetheringTests, TetheringCoverageTests
Change-Id: I7c539f1f4a447b5913164b222601c6113c6fe645
diff --git a/Tethering/tests/unit/Android.bp b/Tethering/tests/unit/Android.bp
index 9b7d683..d1e8f5f 100644
--- a/Tethering/tests/unit/Android.bp
+++ b/Tethering/tests/unit/Android.bp
@@ -82,7 +82,7 @@
 
 android_test {
     name: "TetheringTests",
-    certificate: "platform",
+    platform_apis: true,
     test_suites: [
         "device-tests",
         "mts",