fix fetch-depth: 1
Fixes #ISSUE_NUMBER
Follow up to https://github.com/pytorch/pytorch/pull/75783
Inputs are always strings, and the string wasn't empty, so the if statement always evaluated to true, so it always checked out the extra branches. Add check that the input is literally 'true' in order to checkout the extra branches
tested via #75955
Pull Request resolved: https://github.com/pytorch/pytorch/pull/75957
Approved by: https://github.com/seemethere
