fix(fleet): render error cause is swallowed by the logger

using `errorToObject` when logging error in fleet supervisor

packages/fleet/lib/supervisor/supervisor.ts

@@ -290,7 +290,7 @@ export class Supervisor {
                         const result = await this.execute(operation);
                         if (result.isErr()) {
                             operationSpan?.setTag('error', result.error);
-                            logger.error('Failed to execute operation:', result.error, result.error.cause);
+                            logger.error('Failed to execute operation:', { error: result.error, cause: result.error.cause });
                         }
                     }
                 );