feat: add API endpoint for creating training units from framework slots

- Introduced a new function `createTrainingUnitFromFrameworkSlot` in the API utility, enhancing the ability to create training units directly from framework slots.
- This addition supports improved integration with the training planning features, streamlining the process for users.

frontend/src/utils/api.js

@@ -1072,6 +1072,7 @@ export const api = {
   updateTrainingUnit,
   deleteTrainingUnit,
   quickCreateTrainingUnit,
+  createTrainingUnitFromFrameworkSlot,
   listTrainingPlanTemplates,
   getTrainingPlanTemplate,
   createTrainingPlanTemplate,