[WIP]HIVE-25542: Remove references to Index Configurations

[maheshrajus]

What changes were proposed in this pull request?

Removes the obsolete hive.optimize.index.filter configuration and every reference to it.

Why are the changes needed?

Hive indexes were removed in 4.0.0 (HIVE-18715), but hive.optimize.index.filter survived as dead configuration. The
name is actively misleading — it no longer has anything to do with indexes; it gates ordinary predicate push-down
to the table scan, which hive.optimize.ppd already controls. Keeping it means two knobs for one behavior, a
confusing entry in the config docs, and hundreds of set lines in qtests that suggest a toggle users should care
about.

Does this PR introduce any user-facing change?

Yes, two:

1. The config(hive.optimize.index.filter) is gone. Because hive.optimize.index.filter defaulted to true, anyone leaving it at the default sees
   no behavior change. Anyone explicitly setting it to false to suppress predicate push-down loses that control and
   must use hive.optimize.ppd=false instead. With hive.conf.validation=true (the default), setting the removed key now
   raises an unknown-config error rather than being silently ignored.
2. Error message text changed in LeafFilterFactory for unsupported Parquet FilterPredicate conversions — it now
   recommends only set hive.optimize.ppd=false.

How was this patch tested?

Existing tests

[sonarqubecloud]

Quality Gate passed

Issues
2 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.2% Duplication on New Code

See analysis details on SonarQube Cloud