The shape map needs to be valid inside the excision so that we can support the transition to ringdown code. A previous PR (#6359) extended the transition functions within the excisions, but this was not everything needed. There are a couple problems

1. The shape map doesn't allow points at the center (

   spectre/src/Domain/CoordinateMaps/TimeDependent/Shape.cpp

   Lines 485 to 487 in f46bc13

   	ERROR(
   	"The shape map does not support a (centered) point with radius zero. "
   	"All centered coordinates: "

   ) This needs to be relaxed.
2. The shape map incorrectly divides by the radius if the point is within the excison (

   spectre/src/Domain/CoordinateMaps/TimeDependent/Shape.cpp

   Lines 244 to 245 in f46bc13

   	transition_func_->operator()(centered_coords) *
   	check_and_compute_one_over_radius(centered_coords));

   ). Instead, if the point is within the excision, the shape map should divide by the excision radius.
3. The shape map has no knowledge of what the excision radius is, and therefore can't currently address 2. However the transition functions do. I believe the changes in Make shape map exactly like the one in SpEC #5636 related to having the shape map handle the division by radius were a mistake and that the transition function should be the one to handle the division of the radius.
4. Once this is done, we can add the full grid to inertial map to the excision spheres.