[Fix]: fix rtmdet-inst sdk

[RunningLeon]

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Motivation

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Modification

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[codecov]

Codecov Report

Patch coverage is 11.62% of modified lines.

❗ Current head d9eb6c7 differs from pull request most recent head dc873af. Consider uploading reports for the commit dc873af to get more accurate results

Files Changed	Coverage
mmdeploy/codebase/mmdet/deploy/object_detection.py	0.00%
mmdeploy/mmcv/ops/nms.py	0.00%
...debase/mmdet/models/dense_heads/rtmdet_ins_head.py	3.84%
...oy/codebase/mmdet/deploy/object_detection_model.py	28.57%

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[RunningLeon]

@grimoire @irexyc hi, any comment on this PR?