Enable privacy-sandbox-sdk plugin.

After recent AGP changes, consuming part could be enabled via new DSL,
but producing (SDK) part still experimental and requires property set.

Bug: 305232827
Test: build
Change-Id: I871155326c6a7d6ac8b5b88c8f6a807fa1330813
diff --git a/gradle.properties b/gradle.properties
index c5fd1ca..1d887ab 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -57,7 +57,7 @@
 android.experimental.dependency.excludeLibraryComponentsFromConstraints=true
 # Disallow resolving dependencies at configuration time, which is a slight performance problem
 android.dependencyResolutionAtConfigurationTime.disallow=true
-android.suppressUnsupportedOptionWarnings=android.suppressUnsupportedOptionWarnings,android.dependencyResolutionAtConfigurationTime.disallow,android.experimental.lint.missingBaselineIsEmptyBaseline,android.lint.printStackTrace,android.lint.baselineOmitLineNumbers,android.experimental.disableCompileSdkChecks,android.overrideVersionCheck,android.r8.maxWorkers,android.experimental.privacysandboxsdk.enable,android.experimental.lint.reservedMemoryPerTask,android.experimental.dependency.excludeLibraryComponentsFromConstraints,android.prefabVersion
+android.suppressUnsupportedOptionWarnings=android.suppressUnsupportedOptionWarnings,android.dependencyResolutionAtConfigurationTime.disallow,android.experimental.lint.missingBaselineIsEmptyBaseline,android.lint.printStackTrace,android.lint.baselineOmitLineNumbers,android.experimental.disableCompileSdkChecks,android.overrideVersionCheck,android.r8.maxWorkers,android.experimental.lint.reservedMemoryPerTask,android.experimental.dependency.excludeLibraryComponentsFromConstraints,android.prefabVersion,android.experimental.privacysandboxsdk.plugin.enable,android.experimental.privacysandboxsdk.requireServices
 # Workaround for b/162074215
 android.includeDependencyInfoInApks=false
 # Allow multiple r8 tasks at once because otherwise they can make the critical path longer: b/256187923
@@ -83,5 +83,10 @@
 # Properties we often want to toggle
 ksp.version.check=false
 
+# Enable com.android.privacy-sandbox-sdk plugin
+android.experimental.privacysandboxsdk.plugin.enable=true
+# Allow non-shim usage
+android.experimental.privacysandboxsdk.requireServices=false
+
 # Annotation processors discovery from compile classpath is deprecated
 kapt.include.compile.classpath=false