Fix `long_text` key problem with RMs

[CShorten]

Draft, started with changing

dsp.retrieveEnsemble to dsp.settings.rm

in calls to dspy.Retrieve

=== TODO ==

I now need to remove the long_text key from all the RMs

=== RELATED PROJECT TODO (interface metadata with retrieval) ===

I then need to see how the [1], [2] is formatted in the Signatures when passing in the output from Retrieval. I think this should be self-contained in the Signatures.

[koshyviv]

We're seeing that issue, even with RMs - Issue https://github.com/stanfordnlp/dspy/issues/166

If it helps - the current workaround i am using is https://github.com/stanfordnlp/dspy/pull/486 - but I'm not sure if its the best way forward.

[Athe-kunal]

@CShorten Sorry, I was not able to comprehend the issue here. Can you please elaborate more on it?