No.
Leave in order to seek new employment does not apply to termination of a probationary contract.
During the probationary period an employment contract has not yet been created in due and proper form and the rules applicable to employment contracts and more particularly those concerning termination of an employment contract are applicable only to the extent to which Article L.121-5 of the Labour Code, which governs the probationary period, expressly refers to them.
In fact, Article L.121-5 does not refer to Article L.124-8 and the employer does not therefore have to grant leave to seek new employment, this being provided for only in the case of termination, with the legally prescribed period of notice, of the employment contract by the employer.