Core: Add pruneColumnStats to RewriteManifests

[JoeryH]

Closes #17257.

Adds a pruneColumnStats() option to RewriteManifests. When enabled, column
stats that exceed the table's current write.metadata.metrics.* configuration
are dropped as manifests are rewritten: columns configured none lose all
stats, counts columns lose their bounds, and truncate(n)/full columns are
left unchanged (existing bounds are never re-truncated).

Iceberg infers metrics for up to 100 columns by default, which bloats manifests
and slows planning on wide tables. Tightening the metrics config doesn't shrink
existing manifests today because RewriteManifests copies each data file's
stats verbatim. This option lets users reclaim that space during a manifest
rewrite without rewriting the data files.

Pruning applies only to manifests that are actually rewritten. With no
clusterBy(...) set, enabling it triggers a full rewrite so all data files are
regrouped. The new default interface method throws
UnsupportedOperationException, keeping existing implementors compatible.