Resolve Ty exclude: src/ansys/speos/core/workflow directory

[StefanThoene]

Remove the src/ansys/speos/core/workflow directory exclude from the Ty type check in the CI workflow. Address all type-checking issues in this directory so it passes Ty without the exclude.

Requirements:

• Resolve all typing issues that arise from including src/ansys/speos/core/workflow in Ty type check.
• Ensure no loss of functionality for PySpeos.
• Run the full test suite and verify all tests pass after fixes.
• Do not reintroduce the exclude.

Acceptance Criteria:

• The Ty type check passes without excluding this directory, and all unit tests pass.