IDEA-132514: merge dialog - repaint scrollbar even if thumb position was not changed
(cherry picked from commit 706a85b)
github: keep returned error in exception
(cherry picked from commit 94c38dc)
github: create new token on existing one

with last API changes, GitHub will not return "token" string for existing token.
As we don't implement web-flow, we can't use "create-or-get" as substitution.

So let's just create another token in that case. Better than nothing.
(cherry picked from commit 9e4f2e7)