Fix type of CategoryId (#5696)

Author: pquentin

specification/_types/common.ts

@@ -49,7 +49,7 @@ export type Uri = string
 export type ScrollId = string
 export type ScrollIds = ScrollId | ScrollId[]
 
-export type CategoryId = string
+export type CategoryId = long
 export type ActionIds = string // TODO: check if this should be an array of ActionId
 
 export type Id = string