If you add a regular expression validation to your field, you can use something like this ^([^\|]*|([^\|]*\|[^\|]*){0,6})$
to ensure no more than 7 options are entered.
The numbers at the end of the expression give you the minimum and maximum occurences.
An example of how I set it is below. I wanted - in this case to have no more than three options, so my numbers are {0,2}
:
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