ReportDataWriter: default encoding pinned to UTF-8, not platform default

UTF-8 is a long time documented default and more reliable.

model/report-impl/src/main/java/com/evolveum/midpoint/report/impl/controller/ReportDataWriter.java

@@ -1,12 +1,13 @@
 /*
- * Copyright (C) 2010-2022 Evolveum and contributors
+ * Copyright (C) 2010-2023 Evolveum and contributors
  *
  * This work is dual-licensed under the Apache License 2.0
  * and European Union Public License. See LICENSE file for details.
  */
 package com.evolveum.midpoint.report.impl.controller;
 
 import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
 import java.util.function.Function;
 
 import org.jetbrains.annotations.NotNull;
@@ -86,7 +87,6 @@ default Function<String, String> getFunctionForWidgetStatus() {
      */
     @NotNull
     default Charset getEncoding() {
-        return Charset.defaultCharset();
-//        return StandardCharsets.UTF_8; TODO wouldn't this be better? Definitely more predictable.
+        return StandardCharsets.UTF_8;
     }
 }