fix: Remove parens from postgres source query

[david-dest01]

What this PR does / why we need it:
This PR removes the parens from a query in the PostgresSQLSource which were preventing it to successfully retrieve and materialize from table references.
 
Was previously not supported because of bug

source=PostgreSQLSource(
    name="source_user_events_v0",
    timestamp_field="created_at",
    table="offline_store.user_events"
)

 
Is now supported

source=PostgreSQLSource(
    name="source_user_events_v0",
    timestamp_field="created_at",
    table="offline_store.user_events"
)

source=PostgreSQLSource(
    name="source_user_events_v0",
    timestamp_field="created_at",
    query="select * from offline_store.user_events"
)

 
Which issue(s) this PR fixes:

Fixes #(#3804)

[david-dest01]

@achals lmk if you need anything else here

[achals]

@david-dest01 Do you mind fixing DCO? https://github.com/feast-dev/feast/pull/3807/checks?check_run_id=17817796280

[achals]

Looks good to me otherwise

[job-almekinders]

Hey all, I've opened a similar PR #4026.

If any one of you has the time to take a look this would be highly appreciated! @achals @sudohainguyen