Empty Python operator list output raises a runtime error

### Feature Summary

Python operators that return an empty list fail while normalizing output. The generic list matcher peeks at the first item and raises `StopIteration`, which becomes `RuntimeError: generator raised StopIteration`.

Expected behavior: an empty list produces no output tuples.

Before: empty list output raises a runtime error

After: empty list output produces no tuples

Reproduction evidence:

Call `all_output_to_tuple([])` and consume the returned iterator.

Version and commit evidence:

1.3.0-incubating-SNAPSHOT on main

**Commit Hash (Optional)**
50321e403c82df299a13deb50a7f9849dd93bdba

**Browsers**

Not browser specific

**Relevant log output**

RuntimeError: generator raised StopIteration

### Proposed Solution or Design

Expected behavior: an empty list produces no output tuples.

After: empty list output produces no tuples

### Affected Area

Workflow Engine (Amber)