Bug 36908: (QA follow-up) Proposed improvement to prefernce description

Bug 36908: (QA follow-up) Proposed improvement to prefernce description

I found the initial addition of 'or the branch chosen at login' to the
system preference description more misleading than the original. After
discussion on mattermost and with training staff here at PTFS the best
alternative we could come up with is proposed here.

Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>
(cherry picked from commit 85735e86f4f927d8e455aec08ef90a1381694059)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>