Fix SAT warnings (#14202)

* Fix SAT warnings

- checkstyle.ModifierOrderCheck
- checkstyle.OneStatementPerLineCheck
- checkstyle.NeedBracesCheck
- PMD.UseStandardCharsets
- PMD.UseCollectionIsEmpty
- PMD.UnusedLocalVariable
- PMD.SimplifyBooleanReturns where reasonable, suppress where
readability is better without change
- PMD.SimplifyBooleanExpressions

* Include StandardCharsets

Signed-off-by: Holger Friedrich <mail@holger-friedrich.de>

bundles/org.openhab.binding.ventaair/src/main/java/org/openhab/binding/ventaair/internal/VentaThingHandler.java

@@ -327,10 +327,8 @@ public class VentaThingHandler extends BaseThingHandler {
         }
 
         private boolean messageIsEmpty(DeviceInfoMessage message) {
-            if (message.getCurrentActions() == null && message.getInfo() == null && message.getMeasurements() == null) {
-                return true;
-            }
-            return false;
+            return (message.getCurrentActions() == null && message.getInfo() == null
+                    && message.getMeasurements() == null);
         }
 
         /**