While the pharmacists are free to bring suit against Walgreen's enjoining the above point, the pharmacists will remain unemployed because they have violated a condition of employment.
It would be preferable for their own benefit if they sought employment in another state.
As a practical matter, sure.
As a matter of principle IL's governor, in a unprincipled fashion reminiscent of a dictator, has imposed a rule upon a private business and the private business is caving in to the despotism rather than defending its employees basic rights.