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-front/src/modules/workflow/utils/assertWorkflowWithCurrentVersionIsDefined.tsx

@@ -0,0 +1,15 @@
+import {
+  Workflow,
+  WorkflowVersion,
+  WorkflowWithCurrentVersion,
+} from '@/workflow/types/Workflow';
+import { isDefined } from 'twenty-ui';
+
+// eslint-disable-next-line prefer-arrow/prefer-arrow-functions
+export function assertWorkflowWithCurrentVersionIsDefined(
+  workflow: WorkflowWithCurrentVersion | undefined,
+): asserts workflow is Workflow & { currentVersion: WorkflowVersion } {
+  if (!isDefined(workflow) || !isDefined(workflow.currentVersion)) {
+    throw new Error('Expected workflow and its current version to be defined');
+  }
+}