Encryption integration with REST scan planning

[smaheshwar-pltr]

Feature Request / Improvement

See discussion in #13225 (comment). Lifting out from that thread and the TODO in that PR to a separate issue.

Iceberg encryption should integrate well with scan planning, though it might require encrypting file IO wrapping in certain places. Importantly, it's worth integration testing this too which can be tricky (see #15603).

Query engine

None

Willingness to contribute

• I can contribute this improvement/feature independently
• I would be willing to contribute this improvement/feature with guidance from the Iceberg community
• I cannot contribute this improvement/feature at this time