chore(*): remove unused code (#6781)

The code removed in the PR was flagged as unused by the JetBrains
inspector.

I did a QA on the dev environment but other checks are highly
recommended.

There is one commit by scope to make the review easier.

---------

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

packages/twenty-server/src/engine/workspace-manager/workspace-migration-runner/workspace-migration-runner.service.ts

@@ -1,4 +1,4 @@
-import { Injectable, Logger } from '@nestjs/common';
+import { Injectable } from '@nestjs/common';
 
 import {
   QueryRunner,
@@ -32,8 +32,6 @@ import { customTableDefaultColumns } from './utils/custom-table-default-column.u
 
 @Injectable()
 export class WorkspaceMigrationRunnerService {
-  private readonly logger = new Logger(WorkspaceMigrationRunnerService.name);
-
   constructor(
     private readonly workspaceDataSourceService: WorkspaceDataSourceService,
     private readonly workspaceMigrationService: WorkspaceMigrationService,