feat: Add Type Validation parameter for Pipeline Connections

[sjrl]

Related Issues

• fixes Create a strict vs. lax type comparison option for Pipeline connection validation #8866
• fixes Allow subclassing of Document #8524 by allowing the user to set the type_validation to False for connecting those components together

Proposed Changes

This PR introduces a new connection_type_validation parameter for type compatibility checks and adds _types_are_compatible, and _strict_types_are_compatible functions to support it. The connection_type_validation parameter allows users to configure whether type validation is performed or not. If True then type validation is performed if False then all connections are allowed.

Additionally, I allow this option to be set at the pipeline level or at the individual connection level. I've updated the to_dict and from_dict methods of the pipeline to reflect this.

How did you test it?

• Added unit tests
• Updated existing tests

Notes for the reviewer

@mpangrazzi I'd appreciate your thoughts on the name of the variable and whether you think it makes sense to have the option available at both the pipeline level and the connection level or if it would make sense to only have it present in one spot.

Checklist

• I have read the [contributors guidelines](https://github.com/deepset-ai/haystack/blob/main/CONTRIBUTING.md) and the [code of conduct](https://github.com/deepset-ai/haystack/blob/main/code_of_conduct.txt).
• 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](https://www.conventionalcommits.org/en/v1.0.0/) for my PR title and added ! if this includes breaking changes.
• I documented my code.
• I ran [pre-commit hooks](https://github.com/deepset-ai/haystack/blob/main/CONTRIBUTING.md#installation) and fixed any issues.

[coveralls]

Pull Request Test Coverage Report for Build 13632268125

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.

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Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 39 unchanged lines in 2 files lost coverage.
• Overall coverage increased (+0.007%) to 89.978%

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Files with Coverage Reduction	New Missed Lines	%
core/type_utils.py	2	95.45%
core/pipeline/base.py	37	90.85%

Totals
Change from base Build 13631205752:	0.007%
Covered Lines:	9571
Relevant Lines:	10637

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💛 - Coveralls

[anakin87]

I have marked the failing HF API test -depending on HF API instability- as xfail, so if you merge main, the errors should disappear.

[mpangrazzi]

@sjrl in general, it looks reasonable to me!

As discussed, we may opt to have in first place the connection_type_validation at pipeline level, since it would be probably already enough useful. Then, according to feedbacks / needs, we'll extend it to the connection level. WDYT?

[sjrl]

@mpangrazzi this is ready for another review!

[mpangrazzi]

Looks good!