HDDS-14076. Disable SSTFilteringService when defrag feature is enabled

[smengcl]

What changes were proposed in this pull request?

1. Disable SSTFilteringService when defrag feature is enabled, because defrag is effectively doing the filtering already
2. SSTFilteringService should not run on defragged snapshots

What is the link to the Apache JIRA

https://issues.apache.org/jira/browse/HDDS-14076

How was this patch tested?

• Added UT

[jojochuang]

looks good. i'll let @swamirishi to take another look

[sadanand48]

Thanks @smengcl for the patch. LGTM

[Copilot]

Pull request overview

This PR optimizes snapshot SST filtering by disabling the SSTFilteringService when the defrag service is enabled, since defragmentation already performs filtering operations. It also prevents filtering from running on snapshots that have already been defragged.

Key changes:

• Added logic to disable SSTFilteringService initialization when SnapshotDefragService is enabled
• Enhanced SSTFilteringService to skip defragged snapshots during processing
• Added a new method to expose the last defrag timestamp from snapshot local data

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
KeyManagerImpl.java	Added check to prevent SSTFilteringService from starting when defrag service is enabled
SstFilteringService.java	Added logic to skip defragged snapshots during filtering, preventing redundant work
OmSnapshotLocalDataManager.java	Added getter method to expose last defrag time for determining if a snapshot has been defragged
TestSstFilteringService.java	Added unit test to verify SSTFilteringService is properly disabled when defrag service is enabled

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[jojochuang]

+1 pending CI

[swamirishi]

@smengcl thanks for the patch. Changes look good to me apart from the minor comment I have left.

[smengcl]

Thanks @sadanand48 @jojochuang @swamirishi for the reviews.