Make EmptyTopLevelDeclaration a warning

PiperOrigin-RevId: 501864491
Change-Id: Ic99761f577af39f5d1a15dfe17e81abc94a2bca6

toolchains/default_java_toolchain.bzl

diff --git a/toolchains/default_java_toolchain.bzl b/toolchains/default_java_toolchain.bzl
index 90edad0..9b7ffb9 100644
--- a/toolchains/default_java_toolchain.bzl
+++ b/toolchains/default_java_toolchain.bzl
@@ -56,6 +56,7 @@
     "-Xep:ReturnValueIgnored:OFF",
     # https://github.com/bazelbuild/bazel/issues/16996
     "-Xep:IgnoredPureGetter:OFF",
+    "-Xep:EmptyTopLevelDeclaration:OFF",
 ]
 
 # Default java_toolchain parameters