Delete filter on branch deletion (#13834)

When the target is not in the direct next step ids of the source (step
or trigger), check if there is a filter between both. If yes, delete the
filter and remove it from source next step ids.

Also refactored the existing.

packages/twenty-shared/src/workflow/constants/TriggerStepId.ts

@@ -0,0 +1 @@
+export const TRIGGER_STEP_ID = 'trigger';

packages/twenty-shared/src/workflow/index.ts

@@ -7,6 +7,7 @@
  *                              |___/
  */
 
+export { TRIGGER_STEP_ID } from './constants/TriggerStepId';
 export type {
   WorkflowRunStepInfo,
   WorkflowRunStepInfos,