[infrastructure] move infered nullness warnings to error and update EEA (#8949)

Signed-off-by: Jan N. Klug <jan.n.klug@rub.de>

bundles/org.openhab.binding.magentatv/src/main/java/org/openhab/binding/magentatv/internal/handler/MagentaTVControl.java

@@ -391,10 +391,7 @@ public class MagentaTVControl {
             // direct key code
             return key;
         }
-        if (KEY_MAP.containsKey(key)) {
-            return KEY_MAP.get(key);
-        }
-        return "";
+        return KEY_MAP.getOrDefault(key, "");
     }
 
     /**