Improve reflection registrations in picocli extension

Picocli invokes getDeclaredFields on the declaring classes of annotated
fields so we need to register all fields instead of just the annotated
ones to avoid `MissingReflectionRegistrationError`s at run-time when
using `-H:+ThrowMissingRegistrationErrors` or
`--exact-reachability-metadata`.

Relates to quarkusio#41995

extensions/picocli/deployment/src/main/java/io/quarkus/picocli/deployment/PicocliNativeImageProcessor.java

@@ -16,7 +16,6 @@
 import org.jboss.jandex.AnnotationValue.Kind;
 import org.jboss.jandex.ClassInfo;
 import org.jboss.jandex.DotName;
-import org.jboss.jandex.FieldInfo;
 import org.jboss.jandex.IndexView;
 import org.jboss.jandex.Type;
 import org.jboss.logging.Logger;
@@ -55,7 +54,6 @@ void reflectionConfiguration(CombinedIndexBuildItem combinedIndexBuildItem,
                 DotName.createSimple(CommandLine.Unmatched.class.getName()));
 
         Set<ClassInfo> foundClasses = new HashSet<>();
-        Set<FieldInfo> foundFields = new HashSet<>();
         Set<Type> typeAnnotationValues = new HashSet<>();
 
         for (DotName analyzedAnnotation : annotationsToAnalyze) {
@@ -66,7 +64,6 @@ void reflectionConfiguration(CombinedIndexBuildItem combinedIndexBuildItem,
                         foundClasses.add(target.asClass());
                         break;
                     case FIELD:
-                        foundFields.add(target.asField());
                         // This may be class which will be used as Mixin. We need to be sure that Picocli will be able
                         // to initialize those even if they are not beans.
                         foundClasses.add(target.asField().declaringClass());
@@ -94,20 +91,18 @@ void reflectionConfiguration(CombinedIndexBuildItem combinedIndexBuildItem,
             }
         }
 
+        // Register both declared methods and fields as they are accessed by picocli during initialization
         foundClasses.forEach(classInfo -> {
             if (Modifier.isInterface(classInfo.flags())) {
                 nativeImageProxies
                         .produce(new NativeImageProxyDefinitionBuildItem(classInfo.name().toString()));
-                reflectiveClasses
-                        .produce(ReflectiveClassBuildItem.builder(classInfo.name().toString()).constructors(false).methods()
-                                .build());
+                reflectiveClasses.produce(ReflectiveClassBuildItem.builder(classInfo.name().toString()).constructors(false)
+                        .methods().fields().build());
             } else {
                 reflectiveClasses
-                        .produce(ReflectiveClassBuildItem.builder(classInfo.name().toString()).methods()
-                                .build());
+                        .produce(ReflectiveClassBuildItem.builder(classInfo.name().toString()).methods().fields().build());
             }
         });
-        foundFields.forEach(fieldInfo -> reflectiveFields.produce(new ReflectiveFieldBuildItem(fieldInfo)));
         typeAnnotationValues.forEach(type -> reflectiveHierarchies.produce(ReflectiveHierarchyBuildItem
                 .builder(type)
                 .source(PicocliNativeImageProcessor.class.getSimpleName())