Take exclude vias in unique ids for nmbs

[silamon]

Proposed change

Addressing #121548 (comment). Some users may want to prefer a direct connection with no stops in between and may thus setup 2 config flows between 2 stations whereof one is excluding vias and another one including vias.

I'm hoping this can land in the beta, since I'm changing unique ids that were initially introduced (or were migrated) in this version 2025.2.0.

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