Spark: Fix wap branch delete scan/write to the wrong branch

[yingjianwu98]

Under certain cases, SparkTable, deleteWhere() and canDeleteWhere() do not resolve the WAP (Write-Audit-Publish) branch from the session configuration.

This causes two issues:

• canDeleteWhere() scans the wrong branch's files, so it cannot correctly determine whether the delete can be resolved at the metadata level, causing delete to fail. This is an existing issue across all spark version
• deleteWhere() commits the delete to main instead of the WAP branch, incorrectly dropping data on the main branch. I think it's a recent regression from this PR. Not a Spark expert here but based on my stack trace, I think the spark optimizer: OptimizeMetadataOnlyDeleteFromTable doesn't have the branch information so it will always perform on the main branch.

Fix:

• Use determineReadBranch() in canDeleteWhere() to scan the correct branch
• Use determineWriteBranch() in deleteWhere() to commit to the correct branch

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[github-actions]

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