[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/layout/dropdown/components/Dropdown.tsx

@@ -20,7 +20,7 @@ import { MouseEvent, ReactNode } from 'react';
 import { flushSync } from 'react-dom';
 import { Keys } from 'react-hotkeys-hook';
 import { useRecoilCallback } from 'recoil';
-import { isDefined } from 'twenty-ui';
+import { isDefined } from 'twenty-shared';
 import { sleep } from '~/utils/sleep';
 import { useDropdown } from '../hooks/useDropdown';