Fix dota metric score on 1.x dev.

[Atlantisming]

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Motivation

As many issue that can't reach the mAP on DOTA datasets.

1. [Bug] The RTMDet offical config and checkpoint can't reach the mAP in paper？ #954 (comment)
2. The performances of Oriented RCNN in this version are not consistent with the official results. #955 (comment)

Modification

I solve this problem by easily fixing the precision of score. But the reason is still confused.

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. The documentation has been modified accordingly, like docstring or example tutorials.

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