Bug 23181: Unable to use payment library in ACCOUNT_PAYMENT or ACCOUNT_WRITEOFF notices

Bug 23181: Unable to use payment library in ACCOUNT_PAYMENT or ACCOUNT_WRITEOFF notices

Do to a simple semantic typo, the branches key will always be null for the tables key of the parameters for GetPreparedLetter.

Test Plan:
0) Activate UseEmailReceipts
1) Attempt to use [% branch.branchname %] in the ACCOUNT_PAYMENT notice
2) Note it produces no output
3) Apply this patch
4) Make another payment
5) You should now see the branche's name!

Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Also requires UseEmailReceipts to be activated.

Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
(cherry picked from commit c4466e7d714d32808ee2e553320431005ec7cc69)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>