Use platform certificate for cts

Fix: 223218216
Test: cts passed
Change-Id: I5e8e40594799dec4592ee7e8037296009bc1d724
diff --git a/nearby/tests/cts/fastpair/Android.bp b/nearby/tests/cts/fastpair/Android.bp
index 599fe5c..6dc1af8 100644
--- a/nearby/tests/cts/fastpair/Android.bp
+++ b/nearby/tests/cts/fastpair/Android.bp
@@ -37,6 +37,7 @@
         "general-tests",
         "mts-tethering",
     ],
+    certificate: "platform",
     platform_apis: true,
     sdk_version: "module_current",
     min_sdk_version: "30",