feat: increase Mermaid timeout and make it configurable

[anakin87]

Related Issues

• fixes Pipeline drawing: expose timeout parameter and increase the default #8967

Proposed Changes:

• increase default timeout to 30 seconds (instead of 10)
• expose the timeout parameter in Pipeline.draw and Pipeline.show, so that users can control this behavior.

How did you test it?

CI; new unit test.
I also triggered e2e tests that were failing due to the timeout. -> https://github.com/deepset-ai/haystack/actions/runs/13673782419/job/38229648241?pr=8973

Notes for the reviewer

I think that waiting more than 10 seconds to get a Pipeline rendering is not nice.
I have the feeling that this might be related to the fact that we are now sending compressed data to the server (introduced in #8767) and decompression can also take time on the server. However, there have also been several recent changes in mermaid.ink that may have an impact on rendering times.
In any case, we should monitor what happens in the future.

Checklist

• I have read the contributors guidelines and the code of conduct
• I have updated the related issue with new insights and changes
• I added unit tests and updated the docstrings
• I've used one of the conventional commit types for my PR title: fix:, feat:, build:, chore:, ci:, docs:, style:, refactor:, perf:, test: and added ! in case the PR includes breaking changes.
• I documented my code
• I ran pre-commit hooks and fixed any issue

[coveralls]

Pull Request Test Coverage Report for Build 13674033932

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
• To avoid this issue with future PRs, see these Recommended CI Configurations.
• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 52 unchanged lines in 5 files lost coverage.
• Overall coverage decreased (-0.2%) to 90.066%

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Files with Coverage Reduction	New Missed Lines	%
core/pipeline/draw.py	2	87.29%
components/retrievers/in_memory/bm25_retriever.py	9	79.63%
components/retrievers/in_memory/embedding_retriever.py	11	76.27%
document_stores/in_memory/document_store.py	12	96.14%
core/pipeline/base.py	18	90.85%

Totals
Change from base Build 13673609441:	-0.2%
Covered Lines:	9620
Relevant Lines:	10681

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💛 - Coveralls

[julian-risch]

LGTM! 👍