Separation of religion and government. The government must be kept separate from religious associations in order to be equally effective, so she must follow the dress code if she wants the job. Her religious beliefs or associations are for outside of work not while serving the public. (Isn’t that what libs have always said? And yes, I know it’s not the US, but why should a foreign religion make the rules for the government that is not muslim?)
All you need is ACLU and a liberal federal judge. More than half of current federal judges are Obama appointees including two on the US Ct.