[infrastructure] add external null-annotations (#8848)

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

bundles/org.openhab.binding.sonyprojector/src/main/java/org/openhab/binding/sonyprojector/internal/SonyProjectorException.java

@@ -13,6 +13,7 @@
 package org.openhab.binding.sonyprojector.internal;
 
 import org.eclipse.jdt.annotation.NonNullByDefault;
+import org.eclipse.jdt.annotation.Nullable;
 
 /**
  * The {@link SonyProjectorException} class is used for any exception thrown by the binding
@@ -28,7 +29,7 @@ public class SonyProjectorException extends Exception {
     }
 
     // Constructor that accepts a message
-    public SonyProjectorException(String message) {
+    public SonyProjectorException(@Nullable String message) {
         super(message);
     }
 }