Remove resources from SystemUI-tests

The test resources are provided by SystemUI-tests-base, but
SystemUI-tests was implicitly picking up the main SystemUI tests
while using the com.android.systemui.tests Android package.  This
should have shadowed the R classes from SystemUI-tests-base, but the
classpath order of the R classes was backwards.  Remove the implicit
resources from SystemUI-tests to allow swapping the R classpath
order.

Bug: 294256649
Test: m SystemUITests
Flag: NONE
Change-Id: I41ede1c2899994986dc6e265466626f67a2aec46
diff --git a/packages/SystemUI/Android.bp b/packages/SystemUI/Android.bp
index cc2e84c..04cb88d 100644
--- a/packages/SystemUI/Android.bp
+++ b/packages/SystemUI/Android.bp
@@ -308,6 +308,7 @@
     name: "SystemUI-tests",
     use_resource_processor: true,
     manifest: "tests/AndroidManifest-base.xml",
+    resource_dirs: [],
     additional_manifests: ["tests/AndroidManifest.xml"],
     srcs: [
         "tests/src/**/*.kt",