Make "Rebase stack" button controllable

[gabrielittner]

Can the "Rebase stack" button either follow the "Always suggest updating pull request" option or get an equivalent option?

We'd like to only show it when a rebase is needed and not all the time. In my experience it usually leads to unnecessary rebases and we're using merge queue anyways to make sure that main remains in a good state.

[tylerwillingham]

I'm seeing similar accidental rebases in my company where the presence of the button feels like a necessary action, resulting in wasted CI cycles for otherwise mergable code