Remove mts-tethering from TetheringIntegrationTests

TetheringIntegrationTests is not in MTS (it is not part of the tests
list XML); but CtsTetheringTestLatestSdk contains all its tests and is
part of MTS.

Remove the mts-tethering tag to avoid confusion and get faster build
times.

Change-Id: Ic68fad48179cbf206a8867b81afc76e89f085772
Test: m

Tethering/tests/integration/Android.bp

@@ -79,7 +79,6 @@ android_test {
     defaults: ["TetheringIntegrationTestsDefaults"],
     test_suites: [
         "device-tests",
-        "mts-tethering",
     ],
     compile_multilib: "both",
     jarjar_rules: ":NetworkStackJarJarRules",