Bug in miscentering when mass def=critical and mis_from_backend=False

[combet]

When mis_from_backend=False (i.e., we do some of the miscentering integrations in CLMM rather than relying on the backend), having massdef = critical is ignored and the output always corresponds to massdef = mean.

I just had quick look but I believe this might come from the function below in parent_class.py in theory, where get_rho_m is called in all cases, without checking for what massdef is.

        def _miscentering_params(self, z_cl, mis_from_backend):
        params = None
        if mis_from_backend:
            params = 1, (z_cl,)

        else:
            rho_def = self.cosmo.get_rho_m(z_cl)
            r_s = self.eval_rdelta(z_cl) / self.cdelta
            ...

Pinging @hsinfan1996, @m-aguena

[m-aguena]

@combet good catch