Add test coverage for BandwidthController app commands.

(cherry picked from commit f4dfa682f436398d74e8b55d610b8cca53877246)

Bug: 32073253
Test: netd_{unit,integration}_test pass
Change-Id: I55c6ffd39383f9bb974fa40985d9f03fddfafd7d
Merged-In: I55c6ffd39383f9bb974fa40985d9f03fddfafd7d
1 file changed