Exclude AssimpNet/win DLLs from WebGL builds

[ychaparov]

Proposed change(s)

In the same Unity project, we use URDF-Importer in Unity Editor, but we also have scenes that should be built for WebGL.

As noted in https://github.com/Unity-Technologies/URDF-Importer/issues/201 WebGL builds of a project that has URDF-Importer package always fail, even if URDF-Importer is not used during runtime.

This commit marks the conflicting plugins to exclude WebGL. NOTE: URDF-Importer scripts will not be usable in WebGL builds: Runtime/Unity.Robotics.URDFImporter.asmdef still excludes WebGL. This change allows scenes that don't use URDF-Importer to build.

Useful links (GitHub issues, JIRA tickets, forum threads, etc.)

https://github.com/Unity-Technologies/URDF-Importer/issues/201

Types of change(s)

• [x] Bug fix
• [ ] New feature
• [ ] Code refactor
• [ ] Documentation update
• [ ] Other (please describe)

Testing and Verification

Build a scene that doesn't use URDF-Importer runtime components, while the Unity project has URDF-Importer package

Test Configuration:

• Unity Version: 2022.3.4f1
• Unity machine OS + version: Ubuntu 22.04

Checklist

• [x] Ensured this PR is up-to-date with the dev branch
• [x] Created this PR to target the dev branch
• [x] Followed the style guidelines as described in the Contribution Guidelines
• [ ] Added tests that prove my fix is effective or that my feature works
• [ ] Increased the test coverage criteria by 3%
• [ ] Updated the Changelog and described changes in the Unreleased section
• [ ] Updated the documentation as appropriate

Other comments

[unity-cla-assistant]

All committers have signed the CLA.