[fix] voter record shadowed in common_outbound
This pulls a deeply-nested block of code out to a separate function. It resolves a variable shadow issue, as the voter
record was being overwritten in this code and then used to update the last signed height.
Update: I think the shadowing was actually fine now that I think more about it, but it did cause a lint warning, and breaking out funcs like this is always a good idea.
Edited by akrokr