[Fix] Fix RTMDet-Ins head deploy

[hanrui1sensetime]

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Motivation

bug-report

Modification

Add necessary concat for dummy ops.

BC-breaking (Optional)

None.

Use cases (Optional)

Please use cuda:0 for inference, cpu version will fix in mmdet by @RangiLyu

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 tests to ensure the correctness.
3. If the modification has a dependency on downstream projects of a newer version, this PR should be tested with all supported versions of downstream projects.
4. The documentation has been modified accordingly, like docstring or example tutorials.

[AllentDan]

LGTM

[grimoire]

LGTM