Use the global default cpp_std.

Bug: http://b/344590580
Change-Id: I70183454d165e7d65aa2deee9ef6397e8314619a
diff --git a/Android.bp b/Android.bp
index 11a868d..7e8d682 100644
--- a/Android.bp
+++ b/Android.bp
@@ -143,7 +143,6 @@
         "libgrpc++_reflection",
         "libwmediumd_server",
     ],
-    cpp_std: "c++17",
     visibility: [
         "//device/google/cuttlefish/build",
     ],