Keep static instance field and delete unused field in substitution

* Don't replace `com.jayway.jsonpath.internal.DefaultsImpl#INSTANCE`,
there is no need.

* Delete `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

@@ -9,7 +9,7 @@
 import com.jayway.jsonpath.spi.mapper.JacksonMappingProvider;
 import com.jayway.jsonpath.spi.mapper.MappingProvider;
 import com.oracle.svm.core.annotate.Alias;
-import com.oracle.svm.core.annotate.RecomputeFieldValue;
+import com.oracle.svm.core.annotate.Delete;
 import com.oracle.svm.core.annotate.Substitute;
 import com.oracle.svm.core.annotate.TargetClass;
 
@@ -72,10 +72,8 @@ private static boolean isJson(Object o) {
 
 @TargetClass(className = "com.jayway.jsonpath.internal.DefaultsImpl", onlyWith = HasStrimzi.class)
 final class Target_com_jayway_jsonpath_internal_DefaultsImpl {
-
-    @RecomputeFieldValue(kind = RecomputeFieldValue.Kind.FromAlias)
-    @Alias
-    public static Target_com_jayway_jsonpath_internal_DefaultsImpl INSTANCE = new Target_com_jayway_jsonpath_internal_DefaultsImpl();
+    @Delete // Delete the no longer used mappingProvider
+    private MappingProvider mappingProvider;
 
     @Substitute
     public JsonProvider jsonProvider() {