Move the deserialization of custom XCom Backend to 2.4.0 (#26392)

The change has been cherry-picked so we need to update the docs.

Author: potiuk

airflow/api_connexion/openapi/v1.yaml

@@ -1428,7 +1428,7 @@ paths:
 
             This parameter is not meaningful when using the default XCom backend.
 
-            *New in version 2.5.0*
+            *New in version 2.4.0*
       responses:
         '200':
           description: Success.

airflow/www/static/js/types/api-generated.ts

@@ -3423,7 +3423,7 @@ export interface operations {
          *
          * This parameter is not meaningful when using the default XCom backend.
          *
-         * *New in version 2.5.0*
+         * *New in version 2.4.0*
          */
         deserialize?: boolean;
       };