feat: Add support for Mistral embedding model

[space192]

trafficstars

Description

Add support for Mistral embedding model using mistralai python library

Fixes # (issue)

Type of change

• [x] New feature (non-breaking change which adds functionality)
• [x] Documentation update

How Has This Been Tested?

added tests/embeddings/test_mistralai_embeddings.py to test the integration

• [x] Unit Test

Checklist:

• [x] My code follows the style guidelines of this project
• [x] I have performed a self-review of my own code
• [x] I have commented my code, particularly in hard-to-understand areas
• [x] I have made corresponding changes to the documentation
• [x] My changes generate no new warnings
• [x] I have added tests that prove my fix is effective or that my feature works
• [x] New and existing unit tests pass locally with my changes
• [x] Any dependent changes have been merged and published in downstream modules
• [x] I have checked my code and corrected any misspellings

[CLAassistant]

All committers have signed the CLA.