fix: Fix Pipeline.draw() failing cause of missing socket

[silvanocerza]

Proposed Changes:

Change _to_mermaid_image() so it doesn't call _prepare_for_drawing() as it's already called in _to_mermaid_text().

Calling _to_mermaid_text() right after _prepare_for_drawing() caused the call in _to_mermaid_text() to fail as _prepare_for_drawing() adds some sockets to better show the inputs and outputs of the Pipeline.

How did you test it?

I tested it manually and updated integration tests.

Notes for the reviewer

I ignored the release notes as this bug has been introduced some minutes ago with #6961.

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:.
• I documented my code
• I ran pre-commit hooks and fixed any issue

[coveralls]

Pull Request Test Coverage Report for Build 7845578623

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.002%) to 88.613%

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Totals
Change from base Build 7844859869:	-0.002%
Covered Lines:	4786
Relevant Lines:	5401

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💛 - Coveralls