Delta Migration: Correct `snapshotDataFilesCount` in SnapshotDeltaLakeTable.Result and use Immutable to implement it#7454

jackye1995 merged 5 commits intoapache:masterapache/iceberg:masterfrom

JonasJ-ap:bug_fix/delta_migration_total_file_counterJonasJ-ap/iceberg:bug_fix/delta_migration_total_file_counterCopy head branch name to clipboard