Deconstruct "unconnected" rails filter

[Green Cat]

We can easily deconstruct rails via the filter system...

but it's always annoying when a missplaced 1 rail and not need to "trim" it carfully to not remove the incorrect rail despite the incorect is very very close.

Now, as a reminder, this is when we remove an existing area, so the undo/redo don't help.

And in this case i would like to suggest a very simple new function for the deconstruction planer that will target "unconnected" rail (since we need to add the filter and such, i hope it's clear i assume no one will "accidently" deconstruct their bidirectional train stations).

However this should also include the rail support, and the most tricky part is the train lights since if both rails might have but my suggestion is about how it's sometimes difficult to remove the correct "rail" when it's very very close to one you don't want to deconstruct. So i will just say let's not worry about the light and just add a new feature that at least helps with one issue even if not all