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This CL adds the implementation and tests for the Move function, which
rounds out the functions in the Tab Groups API.

Bug: 1106846
Change-Id: If943b628272aed06b700162dab85ccab4091b842
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2419754
Commit-Queue: Connie Wan <connily@chromium.org>
Reviewed-by: Devlin <rdevlin.cronin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#826003}