[permissions] Enable permissions V1 for all workspaces (#11172)

Closes https://github.com/twentyhq/core-team-issues/issues/526

(for reminder: 
1. Make defaultRoleId non-nullable for an active workspace
2. Remove permissions V1 feature flag
3. Set member role as default role for new workspaces

About 1.:
An active workspace's defaultRoleId should never be null.
We can't rely on a simple postgres NOT NULL constraint as defaultRoleId
will always be initially null when the workspace is first created since
the roles do not exist at that time.

Let's add a more complex rule to ensure that

About 3.:
In the first phase of our deploy of permissions, we chose to assign
admin role to all existing users, not to break any existing behavior
with the introduction of the feature (= existing users have less rights
than before).

As we deploy permissions to all existing and future workspaces, let's
set the member role as default role for future workspaces.
)

packages/twenty-server/src/engine/core-modules/feature-flag/constants/public-feature-flag.const.ts

@@ -9,9 +9,7 @@ type FeatureFlagMetadata = {
 export type PublicFeatureFlag = {
   key: Extract<
     FeatureFlagKey,
-    | FeatureFlagKey.IsWorkflowEnabled
-    | FeatureFlagKey.IsPermissionsEnabled
-    | FeatureFlagKey.IsCustomDomainEnabled
+    FeatureFlagKey.IsWorkflowEnabled | FeatureFlagKey.IsCustomDomainEnabled
   >;
   metadata: FeatureFlagMetadata;
 };
@@ -25,15 +23,6 @@ export const PUBLIC_FEATURE_FLAGS: PublicFeatureFlag[] = [
       imagePath: 'https://twenty.com/images/lab/is-workflow-enabled.png',
     },
   },
-  {
-    key: FeatureFlagKey.IsPermissionsEnabled,
-    metadata: {
-      label: 'Permissions V1',
-      description:
-        'Role-based access control system for workspace security management (Admin/Member)',
-      imagePath: 'https://twenty.com/images/lab/is-permissions-enabled.png',
-    },
-  },
   ...(process.env.CLOUDFLARE_API_KEY
     ? [
         {

packages/twenty-server/src/engine/core-modules/feature-flag/enums/feature-flag-key.enum.ts

@@ -12,7 +12,6 @@ export enum FeatureFlagKey {
   IsCustomDomainEnabled = 'IS_CUSTOM_DOMAIN_ENABLED',
   IsApprovedAccessDomainsEnabled = 'IS_APPROVED_ACCESS_DOMAINS_ENABLED',
   IsNewRelationEnabled = 'IS_NEW_RELATION_ENABLED',
-  IsPermissionsEnabled = 'IS_PERMISSIONS_ENABLED',
   IsWorkflowFormActionEnabled = 'IS_WORKFLOW_FORM_ACTION_ENABLED',
   IsPermissionsV2Enabled = 'IS_PERMISSIONS_V2_ENABLED',
 }