Select amount when changing focus using the tab/backtab key

Commit 8841ae39 introduced a problem
such that the amount was not selected when the focus was changed to the
amountfield using the tab or backtab key. This used to work before with
the KMyMoneyEdit object.

For the standard transaction editor this was fixed by commit
5008fc80 but there are more locations in
the code where this change is necessary.

This change adds the fix to cover all locations which show the above
problem.

BUG: 409371