[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/modules/ui/feedback/dialog-manager/components/Dialog.tsx

@@ -4,8 +4,8 @@ import { useCallback } from 'react';
 import { Key } from 'ts-key-enum';
 
 import { useScopedHotkeys } from '@/ui/utilities/hotkey/hooks/useScopedHotkeys';
+import { isDefined } from 'twenty-shared';
 import { Button } from 'twenty-ui';
-import { isDefined } from '~/utils/isDefined';
 
 import { DialogHotkeyScope } from '../types/DialogHotkeyScope';
 

packages/twenty-front/src/modules/ui/feedback/snack-bar-manager/components/SnackBar.tsx

@@ -16,7 +16,7 @@ import {
   useProgressAnimation,
 } from 'twenty-ui';
 
-import { isDefined } from '~/utils/isDefined';
+import { isDefined } from 'twenty-shared';
 
 export enum SnackBarVariant {
   Default = 'default',

packages/twenty-front/src/modules/ui/feedback/snack-bar-manager/hooks/useSnackBar.ts

@@ -1,7 +1,7 @@
 import { useCallback } from 'react';
 import { useRecoilCallback } from 'recoil';
+import { isDefined } from 'twenty-shared';
 import { v4 as uuidv4 } from 'uuid';
-import { isDefined } from '~/utils/isDefined';
 
 import { SnackBarManagerScopeInternalContext } from '@/ui/feedback/snack-bar-manager/scopes/scope-internal-context/SnackBarManagerScopeInternalContext';
 import {