[CHORE] Avoid isDefined duplicated reference, move it to twenty-shared (#9967)

# Introduction
Avoid having multiple `isDefined` definition across our pacakges
Also avoid importing `isDefined` from `twenty-ui` which exposes a huge
barrel for a such little util function

## In a nutshell
Removed own `isDefined.ts` definition from `twenty-ui` `twenty-front`
and `twenty-server` to move it to `twenty-shared`.
Updated imports for each packages, and added explicit dependencies to
`twenty-shared` if not already in place

Related PR https://github.com/twentyhq/twenty/pull/9941

packages/twenty-front/src/pages/onboarding/CreateWorkspace.tsx

@@ -15,11 +15,11 @@ import { WorkspaceLogoUploader } from '@/settings/workspace/components/Workspace
 import { SnackBarVariant } from '@/ui/feedback/snack-bar-manager/components/SnackBar';
 import { useSnackBar } from '@/ui/feedback/snack-bar-manager/hooks/useSnackBar';
 import { TextInputV2 } from '@/ui/input/components/TextInputV2';
+import { isDefined } from 'twenty-shared';
 import {
   OnboardingStatus,
   useActivateWorkspaceMutation,
 } from '~/generated/graphql';
-import { isDefined } from '~/utils/isDefined';
 
 const StyledContentContainer = styled.div`
   width: 100%;