Deprecate titan text embedding v1 and add v2

Problem/Motivation

Titan Text Embeddings V1 is no longer available and only Titan Text Embeddings V2 exists.

We should deprecate V1 and add a V2 after 📌 Convert models to plugins, remove hardcoded model string checks Needs review goes in.

Steps to reproduce

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes