[Examples][CI] Ensure functionality of examples

[chr-hertel]

Currently the examples are only executed locally, which leads to them being broken and needing fix-ups once in a while - but that's what we have pipelines for :)

There are a few challenges here tho:

• the examples focus on simple executable code snippets instead of PHPUnit test cases
• A ton of secrets for paid services is needed, so we need to be careful how often we execute them - due to rate limits and costs
• Some of them are flaky, especially HuggingFace (unavailable models) and Anthropic (blocking parallel requests)

Is there a solution, that would still enable us to leverage the examples as part of our pipeline?

[OskarStark]

Let's add a workflow which only gets triggered by a Label and executes the examples for OpenAi and removes the label afterwards. We can add an OpenAI key and limit it to this and ChromaDB for example.

[OskarStark]

I will look into it