edb.layout.filter method does not return all primitives with grpc backend

### Before submitting the issue

- [x] I have searched among the existing issues
- [x] I am using a Python virtual environment

### Description of the bug

grpc backend has a bug concerning primitive filtering. Especially on gds based EDB, some primitives are grouped while DotNet list all. decompose method must be used to provide same behavior as DotNet.

### Steps To Reproduce

NA

### Which Operating System are you using?

Windows

### Which Python version are you using?

3.7

### Installed packages

NA

Start at the edb.layout.filter entry point for the grpc backend and inspect how primitive groups are handled for GDS-based EDBs. Read the decompose behavior and compare the result with the DotNet backend; done means filtering returns all primitives consistently.

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