Add failure tests for stealing subgraphs. Minor fix in pipeline.

[mzient]

Follow-up on #5506

Category:

Bug fix (non-breaking change which fixes an issue)
Other (e.g. Documentation, Tests, Configuration)

Description:

This change adds failure tests to the pipeline, detecting:

• uncheckpointable pipeline (with foreign subgraph)
• invalid pipeline (with duplicate node names)

Minor fix:

• error out in Python (instead of C++) when adding a node with a duplicate name

Additional information:

Affected modules and functionalities:

Key points relevant for the review:

Tests:

• Existing tests apply
• New tests added
  • Python tests
  • GTests
  • Benchmark
  • Other
• N/A

Checklist

Documentation

• Existing documentation applies
• Documentation updated
  • Docstring
  • Doxygen
  • RST
  • Jupyter
  • Other
• N/A

DALI team only

Requirements

• Implements new requirements
• Affects existing requirements
• N/A

REQ IDs: N/A

JIRA TASK: N/A

[mzient]

This made the test always pass (the dictionary was empty). There was another check in C++, so it's not critical.

[dali-automaton]

CI MESSAGE: [15740515]: BUILD STARTED

[dali-automaton]

CI MESSAGE: [15740515]: BUILD PASSED