Use login bash shell (for RVM function)

[davispuh]

Currently if I login with SSH with fish as default shell then I get error

myhost ~> ssh otherhost
Have a lot of fun...
Last login: Thu Jan 23 18:53:44 2025
which: no rvm in (/bin:/usr/bin:/bin:/usr/sbin:/sbin)
Welcome to fish, the friendly interactive shell
Type help for instructions on how to use fish
otherhost ~>

Notice which: no rvm in (/bin:/usr/bin:/bin:/usr/sbin:/sbin) which happens every time I login.

I think reason is because bash without --login doesn't run /etc/profile.d/ scripts so RVM is not added to PATH yet. This PR fixes this issue by running bash -l and then I don't have such issue anymore.