Add TimeMachine Reducer Test

The logic to remove tag selector values in the reducer is untested. https://github.com/influxdata/influxdb/blob/master/ui/src/timeMachine/reducers/index.ts#L832.

Add some tests to it, yo!

Originally ideated at: https://github.com/influxdata/influxdb/pull/16226/files#diff-afb81e9ccfb919d0134e48bd7176aa6bR839

Start at ui/src/timeMachine/reducers/index.ts around line 832 and read the reducer logic that removes tag selector values. Review the linked pull request diff for context, then add focused reducer tests covering that behavior and run the relevant TimeMachine reducer test command to confirm the cases pass.

Written by the indexing model from the issue text.