Factor out remoteauth dependencies to variables

This will allow using different values for the variables without having
merge conflicts in the dependencies list for each build rule.

Bug: 295788084
Test: m
Change-Id: I7b64a5a01d1f8139e7ce30ce95903d71cb09de9f
diff --git a/remoteauth/service/Android.bp b/remoteauth/service/Android.bp
index 2ba59da..a40dc15 100644
--- a/remoteauth/service/Android.bp
+++ b/remoteauth/service/Android.bp
@@ -27,6 +27,7 @@
     srcs: [":remoteauth-service-srcs"],
     required: ["libremoteauth_jni_rust_defaults"],
     defaults: [
+        "enable-remoteauth-targets",
         "framework-system-server-module-defaults",
     ],
     libs: [