fix: fix root start script (#5032)

Fixes #5022

See https://nx.dev/recipes/running-tasks/root-level-scripts#setup

packages/twenty-docs/docs/contributor/server/server.mdx

@@ -14,30 +14,30 @@ import DocCardList from '@theme/DocCardList';
 ## Useful commands
 
 These commands should be exectued from packages/twenty-server folder.
-From any other folder you can run `yarn nx <command>` twenty-server.
+From any other folder you can run `npx nx <command>` twenty-server.
 
 ### First time setup
 
 ```
-yarn nx database:reset # setup the database with dev seeds
+npx nx database:reset # setup the database with dev seeds
 ```
 
 ###  Starting the app
 
 ```
-yarn nx start
+npx nx start
 ```
 
 ### Lint
 
 ```
-yarn nx lint
+npx nx lint
 ```
 
 ### Test
 
 ```
-yarn nx test:unit
+npx nx test:unit
 ```
 
 ### Resetting the database
@@ -45,7 +45,7 @@ yarn nx test:unit
 If you want to reset the database, you can run the following command:
 
 ```bash
-yarn nx database:reset
+npx nx database:reset
 ```
 
 :::warning