"couldn't find a terminal to close" when toggling a split when a tab is open

[ioreshnikov]

Hey!

I've noticed a mildly annoying bug: if you open a terminal with :ToggleTerm tab, switch back to the original tab and then call :ToggleTerm split, then you get the error message from the subject. It works perfectly fine in the other order -- a split terminal is being converted into a tab one, but not vice versa.

Best, Ivan