[DISCUSS] Add feature flag: PURGE_VIEWS_ON_DROP

[Dmitri Bourlatchkov]

Hi All,

I propose to add [1] a new feature flag PURGE_VIEWS_ON_DROP to allow
dropping views when DROP_WITH_PURGE_ENABLED is false (default).

The default value of PURGE_VIEWS_ON_DROP is true to match prior behaviour.

Any concerns?

[1] https://github.com/apache/polaris/pull/2369

Thanks,
Dmitri.