Fix applying keyset pagination attributes

What does this MR do?

Fixing a simple Symbol vs String problem when looking up values in a hash. The bug is not user facing (developer facing), it was discovered during development when the new keyset pagination library was first used.

Fix: make sure that we return and process hashes with indifferent access.

Related issue: #325323 (closed)

Does this MR meet the acceptance criteria?

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Related to #325323 (closed)