[spark] Fix missing data for delete hiding remaining records

[ArnavBalyan]

Purpose

• Deleting records from a compacted table makes the remaining records invisible.
• The cow delete uses write only mode, leaving rewritten records at level 0, which first row scans do not read.
• Fix this by ignoring the previous files while keeping compaction enabled, ensuring the rewritten records are promoted to a readable level.

Tests

• UT