Make EmptyTopLevelDeclaration a warning

PiperOrigin-RevId: 501864491
Change-Id: I06db1964964a2a817f6255153d7ee0121397720d

tools/jdk/default_java_toolchain.bzl

diff --git a/tools/jdk/default_java_toolchain.bzl b/tools/jdk/default_java_toolchain.bzl
index cd95cb9..42c87d6 100644
--- a/tools/jdk/default_java_toolchain.bzl
+++ b/tools/jdk/default_java_toolchain.bzl
@@ -54,6 +54,7 @@
     "-Xep:ReturnValueIgnored:OFF",
     # https://github.com/bazelbuild/bazel/issues/16996
     "-Xep:IgnoredPureGetter:OFF",
+    "-Xep:EmptyTopLevelDeclaration:OFF",
 ]
 
 # Default java_toolchain parameters