Removed Duplicate and Wrapper functions

[Arks-06]

Description

Removed duplicate functions from chat.py.
Vector services are now called by global instance.

Type of Change

• Simplification of code

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• New and existing unit tests pass locally with my changes