use problem.extensions.sciml for separation

Author: BSnelling

petab/v2/C.py

@@ -259,7 +259,7 @@
 #: Extensions key in the YAML file
 EXTENSIONS = "extensions"
 #: PEtab SciML extension
-SCIML = "sciml"
+EXT_ID_SCIML = "sciml"
 
 
 # MAPPING