Simplify command execution examples

Removed less reliable command execution method.

Author: whoiskatrin

src/content/docs/sandbox/guides/execute-commands.mdx

@@ -205,9 +205,6 @@ await sandbox.exec('python script.py', {
 
 // Alternative - use absolute path
 await sandbox.exec('python /workspace/my-app/script.py');
-
-// Works but less reliable - change directory in command
-await sandbox.exec('cd /workspace/my-app && python script.py');
 ```
 </TypeScriptExample>