[SG-29236] fix: percy flaky snapshot on Batch change details page

Created by: gitstart-sourcegraph

Descriptions

• The minor different times between 2 call of new Date() makes condition check lastAppliedAt !== null && lastAppliedAt !== createdAt failed and causes percy snapshot changes.
• In this PR, we create a var for new Date() and use it in mocking data to fix the issue

Refs

• SourceGraph Issue
• GitStart ticket