[Bugfix] Delete yapf verify

[okotaku]

Motivation

yapf v0.40.2 has removed verify from FormatCode.

google/yapf@6bc6de1

Please describe the motivation of this PR and the goal you want to achieve through this PR.

Checklist

1. Pre-commit or other linting tools are used to fix the potential lint issues.
2. The modification is covered by complete unit tests. If not, please add more unit test to ensure the correctness.
3. If the modification has potential influence on downstream projects, this PR should be tested with downstream projects, like MMDet or MMCls.
4. The documentation has been modified accordingly, like docstring or example tutorials.