Fix duplicate results in MR pipelines resolver

What does this MR do and why?

See: #362554 (closed)

Fixes a bug where identical records are returned for any two uses of MergeRequest.pipelines in the same query.

The cause of this was the failure to provide sufficiently injective parameters to the query_input.

All uses of the CachingArrayResolver should be checked for this bug. Currently, this resolver is the only consumer for CachingArrayResolver.

How to set up and validate locally

See the linked issue and added tests.

MR acceptance checklist

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