Python: Add Jina AI connecter with text embedding and example.

[SebasX5]

Motivation and Context

Implementation of the Jina AI connector with text embedding and an example file to display its functionality.
Closes #2063

Description

1. Implemented Jina AI connector with text embedding.
2. Added an example file to python/samples/kernel-syntax-examples
3. Added a Jina test file to python/tests/integration/embeddings

Contribution Checklist

• The code builds clean without any errors or warnings
• The PR follows the SK Contribution Guidelines and the pre-submission formatting script raises no violations
• All unit tests pass, and I have added new tests where possible
• I didn't break anyone 😄

[nacharya1]

@SebasX5 FYI: We recently updated our contributing guidelines [here](https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md#adding-plugins-and-memory-connectors , stating we are not directly adding plugin and connectors directly into the SDK repository. We are encouraging the community to host their own plugins and connectors separately in their own repositories. At the time we are exploring how we can provide a way to discover plugins and connectors and should have an update soon. I am going to close this issue given our change in contribution guidelines.