openAIImages should derive from needsAPIKey

Author: ccreutzi

openAIImages.m

@@ -1,4 +1,4 @@
-classdef openAIImages
+classdef openAIImages < llms.internal.needsAPIKey
 %openAIImages Connect to Images API from OpenAI.
 %
 %   MDL = openAIImages creates an openAIImages object with dall-e-2
@@ -38,10 +38,6 @@
         TimeOut
     end
 
-    properties (Access=private)
-        APIKey
-    end
-
     methods
         function this = openAIImages(nvp)
             arguments