fix: Fix for materializing entityless feature views in Snowflake

[JohnLemmonMedely]

What this PR does / why we need it: When using an entityless featureview with a Snowflake offline store it fails to materialize correctly.

Which issue(s) this PR fixes:

Fixes # 3960

[franciscojavierarceo]

@JohnLemmonMedely can you provide more context on this one? Do we support entityless feature views outside of this? Or is this a bit of a hack?

[JohnLemmonMedely]

@JohnLemmonMedely can you provide more context on this one? Do we support entityless feature views outside of this? Or is this a bit of a hack?

Yes, I hit this bug when setting up a feature view like this. It looks like the documentation calls this "Feature views without entities" but the code refers to it as "entityless feature views".

In this case the original code was checking for an entityless feature view by checking if entity_columns is truthy. I'm not sure if this was once a valid check or not but today in Feast entityless feature views are given a dummy entity_column instead.

[JohnLemmonMedely]

@franciscojavierarceo Does my above comment answer your question? Anything else I need to do before merging this in?

[JohnLemmonMedely]

this lgtm. your pr title lint failed

Thanks @franciscojavierarceo, I think I fixed the PR title earlier so the check is passing now.