Auto merge of #29546 - mrobinson:fix-build-warnings, r=jdm

Fix some build warnings

Change a use of `extern crate` to be simply `use`, which is what the compiler suggests. In addition, with the change, one of the uses is redundant. In addition, remove two unused `use` statements.

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- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes do not require tests because they fix some warnings.

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0 files changed, 0 insertions, 0 deletions