Fix display of most current Nomination list (election polls)

[Elblinator]

Describe the bug
The most current election poll displays a too big list (double the items)

How to Reproduce

1. create a new election
2. put a candidate onto the candidate list
3. create a poll with voting method: Yes/No/Abstain per list
4. Nomination list has empty items
5. create a new poll with voting method: Yes/No/Abstain per list
6. The newest polls nomination list has the same problems the old one(s) are correct again

Expected behaviour:
The nomination list should only display the candidates

[reiterl]

It seems to be a wrong use of the 'for ... track...' in the template in combination with this option create new list everytime it is called.