Add lodash GroupBy as taint step

[Vasco-jofra]

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Adds _.groupBy as a taint step.

This is analogous to the GroupByTaintStep class, which does the same for Object and Map.

https://github.com/github/codeql/blob/d83cbde1cb1263fb476a55ea5fd7972307138905/javascript/ql/lib/semmle/javascript/Collections.qll#L158C1-L166C4