Add source jar to transitive jars in JavaProtoAspect

Ensures the source jar for java_proto_library is included in the set of
transitive source jars as is expected.

Fixes https://github.com/bazelbuild/bazel/issues/11830

PiperOrigin-RevId: 335592987
diff --git a/src/main/java/com/google/devtools/build/lib/rules/java/proto/JavaProtoAspect.java b/src/main/java/com/google/devtools/build/lib/rules/java/proto/JavaProtoAspect.java
index cf1da52..7b026ff 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/java/proto/JavaProtoAspect.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/java/proto/JavaProtoAspect.java
@@ -236,7 +236,7 @@
                 .build();
         JavaSourceJarsProvider sourceJarsProvider =
             JavaSourceJarsProvider.create(
-                NestedSetBuilder.<Artifact>emptySet(Order.STABLE_ORDER),
+                NestedSetBuilder.create(Order.STABLE_ORDER, sourceJar),
                 ImmutableList.of(sourceJar));
 
         aspect.addProvider(ruleOutputJarsProvider).addProvider(sourceJarsProvider);