fix: fixes gets on many-to-many with non-primary target key #11587

[aheuermann]

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Description of change

Closes #11587
When using a belongsToMany using a non-primary key as the targetKey it is ignored and either no results are returned (if the columns on the join table are of the same type as the pk) or fails if different types.

[codecov]

Codecov Report

Merging #11778 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master   #11778   +/-   ##
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  Coverage   96.26%   96.26%           
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  Files          94       94           
  Lines        9191     9191           
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  Hits         8848     8848           
  Misses        343      343

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