Run R8 with the necessary classpath classes

R8 emits "missing class" warnings when optimizing service-connectivity
because service-connectivity combines several already built static_libs
(service-connectivity, service-connectivity-t, service-nearby), but does
not specify any classpath library, which are actually needed for R8.

This causes wrong optimizations, where R8 would sometimes strip out code
that it thinks is unused (because it considers it unreachable due to the
missing class, or it does not know the superclass of a callback and
thinks the overridden methods cannot be called).

Add the necessary classpath libraries to remove the warnings.

Bug: 226127213
Bug: 239990030
Test: m service-connectivity, see no "Missing class" warnings
Change-Id: I1eaa39b70da4b540e3a3e8e798bec1359b5bf533
diff --git a/framework-t/Android.bp b/framework-t/Android.bp
index 8c32ded..80477f1 100644
--- a/framework-t/Android.bp
+++ b/framework-t/Android.bp
@@ -116,6 +116,7 @@
         "//packages/modules/Connectivity/Tethering/apex",
         // In preparation for future move
         "//packages/modules/Connectivity/apex",
+        "//packages/modules/Connectivity/service", // For R8 only
         "//packages/modules/Connectivity/service-t",
         "//packages/modules/Nearby/service",
         "//frameworks/base",