Adjust CPS Performance test margins

Adjust CPS Performance test margins

As per discussion in the CPS weekly meeting dated Feb 11, 2026 the performance margin for following tests is to be adjusted:

 - Graph #51 Read datatrees using openroadm whole
 - Graph #52 Read datatree with all descendants
 - Graph #53 Read datatree with direct descendant
 - Graph #71 Saving list of 400 devices
 - Graph #81 Creating modified openroadm anchor
 - Graph #82 Clean up for CPS Delta
 - Graph #83 Delta test setup

Issue-ID: CPS-3173
Change-Id: If691691c8356dae9344a6947cf0c98f66e35c0a4
Signed-off-by: Arpit Singh6 <AS00745003@techmahindra.com>