[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/utils/__tests__/isDefined.test.ts

@@ -1,15 +0,0 @@
-import { isDefined } from '~/utils/isDefined';
-
-describe('isDefined', () => {
-  it('returns true if value is not undefined nor null', () => {
-    expect(isDefined('')).toBe(true);
-  });
-
-  it('returns false if value is null', () => {
-    expect(isDefined(null)).toBe(false);
-  });
-
-  it('returns false if value is undefined', () => {
-    expect(isDefined(undefined)).toBe(false);
-  });
-});