fix: Import error when calling get_feature_view for feature views with SparkSource

[dnlbunting]

Fixes #3872

Add import guard around SparkSession import so the registry can be loaded in environments without PySpark installed

What this PR does / why we need it:

Which issue(s) this PR fixes:

Fixes #

[redhatHameed]

@dnlbunting can you fix the DCO check, here is the guideline https://docs.feast.dev/project/development-guide#signing-off-commits

[ElliotNguyen68]

hi @dnlbunting , please check my comment from the issues section

[jeremyary]

PR appears to be left behind, no response for a few months now. If you'd like to re-open the issue, please drop us a comment thanks