Add tests for the chatbot sample and allow them to run with platform BOMs

[fedinskiy]

Partial replacement for #1742
Based on #1792

[fedinskiy]

According to the failures, I will need to disable the tests by default. Will do this on Monday, and possibly will add an integration test.
For now I need to make sure, that you're not against these changes, @geoand

[geoand]

It seems to make sense

[fedinskiy]

test failures:
codestarts, docs, samples, tetsing-internal, multiple-providers, ollama, rag: Error downloading JBang from https://github.com/jbangdev/jbang/releases/latest/download/jbang.tar

I presume, that there are some problems with jbang site or with respective GH action, and this error is not related to the content of the PR. @geoand could you review the PR?

[geoand]

Seems reasonable

[quarkus-bot]

Status for workflow Build (on pull request)

This is the status report for running Build (on pull request) on commit b1fc04c.

✅ The latest workflow run for the pull request has completed successfully.

It should be safe to merge provided you have a look at the other checks in the summary.