Intermodal edge for router gets negative length assigned

[m-kro]

Can be found using the example data from #14201 . The access is defined at the very end of the edge, leading to a slightly negative length for intermodal (pedestrian) edge 655451190#0_fwd376.24. Then this triggers

https://github.com/eclipse-sumo/sumo/blob/9513a6fa80b586c1e54ed98b6bceb26442f051a6/src/utils/router/IntermodalEdge.h#L197-L198

[m-kro]

Example data in S:\Bugreports\14201