GRHD: fix atmosphere freezing and evolution logic

Fixes the following issues with the current implementation:

• update_atm_domain_of_dependence! did not distinguish between points

  1. whose neighbors are also in the bulk,
  2. where one neighbor is on an interface,
  3. where the point itself is on an interface.

  These cases are already properly handled in 2d.

• stop_atmosphere_evolution_* methods did not account for the c2p_freeze_atm flag, which essentially prevented the atmosphere to ever evolve.

• update_atm_domain_of_dependence! was activated by setting c2p_dynamical_atm, but it should be controlled by c2p_enforce_causal_atm

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Additional fixes with less impact:

• remove unused parameter id_atmosphere_density from GRHD section
• c2p_set_atmosphere_on_failure should really suppress any errors appearing in the cons2prim