Add optional validation failure to create and update pipeline tool

[mathislucka]

Overview

We always want to run validation for the create_pipeline and update_pipeline tools but we want to make breaking after an invalid response optional. Tools are located in src/deepset_mcp/tools/pipeline.py

Requirements

• update and create pipeline receive a parameter that allows to create or update pipelines even if validation fails
• by default, the tools create or update pipelines, even if validation fails
• if the operation is done with validation failure, the creation message is returned alongside the error messages from the validation response (look at to llm readable string functions)

[mathislucka]

Your changes so far look good! Now just add some tests for the new parameter and raise the PR.