Allow tethering module to depend on Perfetto SDK

This reduces min_sdk_version from S (31) to 30 (R) and allows the
tething module in the list of apexes. As far as I'm aware, nothing
in the Perfetto client library should depend on Android, let alone
Android S.

Bug: 246985031
Test: ran example_custom_data_source on a Pixel 5 w/ Android 30 (R)
Change-Id: I458169dd1dc85e25f26154c9529ddd682d95d46b
diff --git a/Android.bp b/Android.bp
index a0d2e95..b678979 100644
--- a/Android.bp
+++ b/Android.bp
@@ -914,8 +914,9 @@
         "//apex_available:platform",
         "com.android.art",
         "com.android.art.debug",
+        "com.android.tethering",
     ],
-    min_sdk_version: "S",
+    min_sdk_version: "30",
 }
 
 // GN: //src/perfetto_cmd:perfetto