Reset unused field in substitution

Reset `com.jayway.jsonpath.internal.DefaultsImpl#mappingProvider` in
`io.smallrye.reactive.kafka.graal.Target_com_jayway_jsonpath_internal_DefaultsImpl`
since it's no longer used.

Closes quarkusio#37862

extensions/kafka-client/runtime/src/main/java/io/smallrye/reactive/kafka/graal/StrimziSubstitutions.java

@@ -77,6 +77,12 @@ final class Target_com_jayway_jsonpath_internal_DefaultsImpl {
     @Alias
     public static Target_com_jayway_jsonpath_internal_DefaultsImpl INSTANCE = new Target_com_jayway_jsonpath_internal_DefaultsImpl();
 
+    // Reset the field to null since it's no longer used.
+    // Works around https://github.com/quarkusio/quarkus/issues/37862
+    @RecomputeFieldValue(kind = RecomputeFieldValue.Kind.Reset)
+    @Alias
+    private MappingProvider mappingProvider;
+
     @Substitute
     public JsonProvider jsonProvider() {
         return new JacksonJsonNodeJsonProvider();