[BUG] Unable to install with only wheels due to py-ubjson dependency

## Bug Description **Summary**: Unable to install with only wheels due to py-ubjson dependency **Expected Behavior**: Be able to download wheels for autobahn and all it's declared dependencies, and thus be able to install without any source code based installation requirements. **Actual Behavior**: Unable to accomplish this due to unconditional dependency on py-ubjson that was added in 25.12.1 (since py-ubjson does not provide a wheel). ## Reproduction Steps Execute: ``` pip download autobahn==25.12.2 -d /wheels --platform manylinux_2_34_aarch64 --platform manylinux_2_28_aarch64 --platform manylinux_2_17_aarch64 --platform manylinux2014_aarch64 --only-binary :all: ``` **Minimal Reproducible Example**: Execute: ``` pip download autobahn==25.12.2 -d /wheels --platform manylinux_2_34_aarch64 --platform manylinux_2_28_aarch64 --platform manylinux_2_17_aarch64 --platform manylinux2014_aarch64 --only-binary :all: ``` ## Environment - **Package**: autobahn-python - **Version**: 25.12.2 - **Python Version**: CPython 3.13 - **Operating System**: Ubuntu 25.10 & 26.04 on aarch64 (arm64) - **Framework**: n/a ## Additional Context **Error Messages**: ``` ERROR: Could not find a version that satisfies the requirement py-ubjson>=0.16.1 (from autobahn) (from versions: none) ERROR: No matching distribution found for py-ubjson>=0.16.1 ``` **Relevant Logs**: ``` n/a ``` **Screenshots**: <img width="868" height="330" alt="Image" src="https://github.com/user-attachments/assets/1359dfec-1d8e-4dcb-bf70-e85524c6c6da" /> **Related Issues**: Seems related to b063660? ## Checklist - [x] I have searched existing issues to avoid duplicates - [x] I have provided a minimal reproducible example - [x] I have included version information - [x] I have included error messages/logs