Activate/Deactivate workflow and Discard Draft (#7022)

## Setup

This PR can be tested only if some feature flags have specific values:

- `IsWorkflowEnabled` equals `true`
- `IsQueryRunnerTwentyORMEnabled` equals `false`

These feature flags weren't committed to don't break other branches.

## What this PR brings

- Display buttons to activate and deactivate a workflow version and a
button to discard the current draft version. I also scaffolded a "Test"
button, which doesn't do anything for now.
- Wired the activate, deactivate and discard draft buttons to the
backend.
- Made it possible to "edit" active and deactivated versions by
automatically creating a new draft version when the user tries to edit
the version.
- Hide the "Discard Draft", button if the current version is not a draft
or is the first version ever created.
- On the backend, don't consider discarded drafts when checking if a new
draft version can be created.
- On the backend, disallow deleting the first created workflow version.
Otherwise, we will end up with a blank canvas in the front end, and it
will be impossible to recover from it.
- On the backend, disallow running deactivation steps if the workflow
version is not currently active. Previously, we were throwing, which is
unnecessary as it's a valid case.

## Spotted bugs that we must dive into

### Duplicate workflow versions in Apollo cache


https://github.com/user-attachments/assets/7cfffd06-11e0-417a-8da0-f9a5f43b84e2

---------

Co-authored-by: Charles Bochet <charles@twenty.com>

packages/twenty-server/src/modules/workflow/common/workspace-services/workflow-version-validation.workspace-service.ts

@@ -1,5 +1,7 @@
 import { Injectable } from '@nestjs/common';
 
+import { IsNull, Not } from 'typeorm';
+
 import {
   CreateOneResolverArgs,
   DeleteOneResolverArgs,
@@ -11,12 +13,12 @@ import {
   WorkflowQueryValidationException,
   WorkflowQueryValidationExceptionCode,
 } from 'src/modules/workflow/common/exceptions/workflow-query-validation.exception';
-import { assertWorkflowVersionIsDraft } from 'src/modules/workflow/common/utils/assert-workflow-version-is-draft.util';
-import { WorkflowCommonWorkspaceService } from 'src/modules/workflow/common/workspace-services/workflow-common.workspace-service';
 import {
   WorkflowVersionStatus,
   WorkflowVersionWorkspaceEntity,
 } from 'src/modules/workflow/common/standard-objects/workflow-version.workspace-entity';
+import { assertWorkflowVersionIsDraft } from 'src/modules/workflow/common/utils/assert-workflow-version-is-draft.util';
+import { WorkflowCommonWorkspaceService } from 'src/modules/workflow/common/workspace-services/workflow-common.workspace-service';
 
 @Injectable()
 export class WorkflowVersionValidationWorkspaceService {
@@ -48,6 +50,8 @@ export class WorkflowVersionValidationWorkspaceService {
         where: {
           workflowId: payload.data.workflowId,
           status: WorkflowVersionStatus.DRAFT,
+          // FIXME: soft-deleted rows selection will have to be improved globally
+          deletedAt: IsNull(),
         },
       });
 
@@ -84,5 +88,25 @@ export class WorkflowVersionValidationWorkspaceService {
       );
 
     assertWorkflowVersionIsDraft(workflowVersion);
+
+    const workflowVersionRepository =
+      await this.twentyORMManager.getRepository<WorkflowVersionWorkspaceEntity>(
+        'workflowVersion',
+      );
+
+    const otherWorkflowVersionsExist = await workflowVersionRepository.exists({
+      where: {
+        workflowId: workflowVersion.workflowId,
+        deletedAt: IsNull(),
+        id: Not(workflowVersion.id),
+      },
+    });
+
+    if (!otherWorkflowVersionsExist) {
+      throw new WorkflowQueryValidationException(
+        'The initial version of a workflow can not be deleted',
+        WorkflowQueryValidationExceptionCode.FORBIDDEN,
+      );
+    }
   }
 }