What should we add?

Right now when there are multiple connected components in the circuit when we're running heuristic scoring for VF2Layout or VF2PostLayout we end up spending a great deal of time evaluating different potential layouts. This is because the number of combinations of layouts is quite high when there are multiple connected components in the circuit as there is a lot of freedom of placement and we evaluating each potential combination of valid placement for each connected component. This is a similar problem to #9026 (and fixed in #9148) but that was for the case of single qubit components in the circuit (this is causing poor performance in #9802).

To address this we should investigate expanding the approach taken in #9148 to larger connected components instead of just single qubit connected components. This would basically involve sorting each circuit connected component by number of operations and placing the connected components with the most operations first (maybe weighting towards more 2q ops than single qubit) and then iterate over each connected component and place them on the lowest error subgraphs in sequence. We likely will miss some potential layouts in this approach, but those lost possibilities shouldn't be significant.

For the implementation this might be a bit more involved, because rustworkx.vf2_mapping() doesn't support providing partial input mappings and I'm not sure the best mechanism to handle to go about doing this.