Cleanup UnnestNode filter removal

[kasiafi]

Related change: https://github.com/trinodb/trino/pull/20994/commits/bdbdc8f8ddb21c9e06a89f6e6666267d0e409f1b

Includes:

• logical change: extracting source predicate for relevant join types in EffectivePredicateExtractor
• fixes to GraphvizPrinter and PlanPrinter regarding UnnestNode's join type
• code and comment cleanup

By removing filter from UnnestNode, we lost distinction between Unnest being in the context of a join or standalone. Given the way Unnest is planned, it is not incorrect. However, this information sometimes cannot be restored in plan printers.

No docs or release notes needed.

[kasiafi]

@lukasz-stec I added a test in TestLogicalPlanner, similar to the one you suggested.

[kasiafi]

@losipiuk ac