added .opus as supported audio extension (#2832)
* added .opus as supported audio extension
* Update libs/libcommon/src/libcommon/viewer_utils/asset.py
* test copy and conversion of wav and opus files
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Co-authored-by: Sylvain Lesage <severo@rednegra.net>
Co-authored-by: Sylvain Lesage <sylvain.lesage@huggingface.co>
