feat: Replace Identity Comparison with Equality Comparison in parse_repo

[srausser]

What this PR does / why we need it:
This Pull Request updates the parse_repo function in repo_operations.py, transitioning from the identity operator is to the equality operator == for object comparisons.

Previously, the parse_repo function utilized the is operator to compare Feast objects such as data sources, feature views, and entities. The is operator compares if two variables point to the exact same object in memory. However, this approach can be overly restrictive.

When Feast objects are imported across different parts of the repository definition files, they may not share the same memory address, even though they represent the same logical object. This discrepancy led to erroneous distinctions between objects that should have been recognized as identical.

To address this, I've replaced the is operator with ==. The == operator evaluates whether two variables are equal in value, independent of their memory addresses. This adjustment enhances the flexibility and accuracy of object comparison within parse_repo, permitting objects imported across the repository to be correctly recognized as equal when their values match.

Which issue(s) this PR fixes:

Fixes #3312

[feast-ci-bot]

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[srausser]

/assign @DvirDukhan

[srausser]

closing since i can't seem to replicate the errors im seeing in my production repository