Remove redundant imports

[FreezyLemon]

These result in warnings on 1.78 (current nightly). For example:

warning: the item `Pixel` is imported redundantly
  --> src/bin/stats.rs:14:21
   |
10 | use av_metrics::video::*;
   |     -------------------- the item `Pixel` is already imported here
...
14 | use rav1e::{Packet, Pixel};
   |                     ^^^^^

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 88.54%. Comparing base (3c3a26f) to head (86e6045). Report is 3 commits behind head on master.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #3354 +/- ## ========================================== + Coverage 88.52% 88.54% +0.01% ========================================== Files 89 89 Lines 28323 28355 +32 ========================================== + Hits 25074 25107 +33 + Misses 3249 3248 -1 ```

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.