Fix invalid sub codes in MoroccoAI summer school entry

Author: gmberton

site/_data/summerschools.yml

@@ -855,7 +855,7 @@
   date: "September 8 - September 12, 2025"
   start: 2025-09-08
   end: 2025-09-12
-  sub: ['ML', 'NLP', 'CV', 'GenerativeAI', 'Multimodal']
+  sub: ['ML', 'NLP', 'CV', 'GenAI']
   note: "Applications open June 23, 2025; acceptance notifications sent July 25, 2025."
   email: "team@morocco.ai"
   description: