Remove invalid NoSQL Python link

[fengfeng-zi]

Description

Remove the Write a NoSQL Database in Python entry from the Python Miscellaneous section in README.md.

Motivation and Context

This change removes a stale tutorial entry so readers are not sent to an invalid resource.

How Has This Been Tested?

Reviewed the local diff to confirm the change is limited to a single README entry removal.

Types of changes

• Content Update (change which fixes an issue or updates an already existing submission)
• New Article (change which adds functionality)
• Documentation change

Checklist:

• My code follows the code style of this project.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have made checks to ensure URLs and other resources are valid