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/tests/unit/Android.bp b/remoteauth/tests/unit/Android.bp
index 4b92d84..27e5418 100644
--- a/remoteauth/tests/unit/Android.bp
+++ b/remoteauth/tests/unit/Android.bp
@@ -18,7 +18,10 @@
 
 android_test {
     name: "RemoteAuthUnitTests",
-    defaults: ["mts-target-sdk-version-current"],
+    defaults: [
+        "enable-remoteauth-targets",
+        "mts-target-sdk-version-current"
+    ],
     sdk_version: "test_current",
     min_sdk_version: "31",