Bump submodules/googletest from 71815bb to df1544b

Bumps [submodules/googletest](https://github.com/google/googletest) from `71815bb` to `df1544b`.
- [Release notes](https://github.com/google/googletest/releases)
- [Commits](google/googletest@71815bb...df1544b)

---
updated-dependencies:
- dependency-name: submodules/googletest
  dependency-type: direct:production
...

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