Add feature flag for force L3 dev option

Bug: 301669353
Change-Id: I289bed846982e94584fdb067e84186a61587d578

aconfig/Android.bp

@@ -25,3 +25,14 @@ java_aconfig_library {
     name: "factory_reset_flags_lib",
     aconfig_declarations: "factory_reset_flags",
 }
+
+aconfig_declarations {
+    name: "media_drm_flags",
+    package: "com.android.settings.media_drm",
+    srcs: ["media_drm/*.aconfig"],
+}
+
+java_aconfig_library {
+    name: "MediaDrmSettingsFlagsLib",
+    aconfig_declarations: "media_drm_flags",
+}

aconfig/media_drm/settings_mediadrm_flag_declarations.aconfig

@@ -0,0 +1,8 @@
+package: "com.android.settings.media_drm"
+
+flag {
+    name: "force_l3_enabled"
+    namespace: "media_drm"
+    description: "Feature flag of forcing L3"
+    bug: "301669353"
+}