Fix exception in Publish unit test results step (#20007)
### Description
Test results files are all in RelWithDebInfo\RelWithDebInfo directory.
It's not necessary to stat the directory of _deps
### Motivation and Context
Recently this exception in zip-nuget pipleine occurs many times.
`##[error]Error: Failed find: EPERM: operation not permitted, stat
'D:\a\_work\1\b\RelWithDebInfo\_deps\flatbuffers-src\java\src\test\java\DictionaryLookup'`
https://dev.azure.com/aiinfra/Lotus/_build/results?buildId=426981&view=logs&j=75fc0348-fe99-522b-3acb-90fd80ac5271&t=5d4ebcc1-bcde-574d-6f4e-8abd0f04ae4b
