fix(examples): better error handling and other fixes

[ajbozarth]

Which issue(s) does this pull-request address?

Ref #336

Description

Various improvements to existing examples:

• Add better and more consistent error handling, this also cleans up pytest e2e output
• set options.execution.max_iterations default to math.inf to match TS implementation
• various "mypy" fixes (actually just PyCharm checker)
• conditionally run watsonx and openai examples in pytest
• fix pytest that was whacking the ollama env vars for future tests (like examples)

Checklist

• I have read the contributor guide
• I have signed off on my commit
• Tests are included
• Documentation is changed or added
• Commit messages and PR title follow conventional commits

[ajbozarth]

If I do any more work on existing examples this weekend I'll add here, otherwise I'll open separate PRs for new examples.

[ajbozarth]

Also @Tomas2D the e2e tests are still failing, but in a smaller number now. The following examples fail intermittently when run (even outside pytest):

• agents/simple.py
• tools/duckduckgo.py
• tools/openmeteo.py
• workflows/multi_agents.py

The first three usually fail on ToolInput validation, but sometimes on the old LinePrefixParserError('The generated output does not adhere to the schema.\nNothing valid has been parsed yet!')

multi_agents.py sometimes also fails on Tool validation, but is generally still failing the same way as test_multi_agents_workflow_creation, which from a bit more testing seems to be at somewhat caused by the existence of multiple agents in the workflow.

[Tomas2D]

Can you move all try/except blocks within example body into the __main__ block?
It would be easier to read and generally look better in the docs (in the future we might stip the __main__ block entirely in the documentation)

[ajbozarth]

Can you move all try/except blocks within example body into the main block?
@Tomas2D done, all examples now have the same __main__ with centralized error handling

[Tomas2D]

Not sure whether sys.exit(e.explain()) is a good practise.

[ajbozarth]

Not sure whether sys.exit(e.explain()) is a good practise

This was what was generally suggested on stack overflow, I had doubts at first too, but it works really well in practice