Enhance MacOS instructions for Qiskit C API to clarify Python dylib requirement

[cometta]

URL to the relevant guide or resource

The current documentation (https://quantum.cloud.ibm.com/docs/en/guides/install-c-api ) for installing the Qiskit C API on MacOS does not clearly emphasize the requirement to include Python's dylib library path.

I will fix this

Select all that apply

• new content request
• typo
• code bug
• out-of-date content
• broken link
• other

Describe the fix or the content request.

I suggest adding a dedicated note specifically for MacOS users that explicitly states:

The Python dylib is required for the Qiskit C API to function on MacOS
Exactly where to find this library (typical locations)

For new content requests - if the request is accepted, do you want to write the content?

I will write (or already have written) a draft of the proposed content

[cometta]

The PR is ready