Fea: Modify the A/B testing evaluation UI to look like the other evaluation views

[mmabrouk]

Is your feature request related to a problem? Please describe.
There's an inconsistency in the design of the A/B testing UI compared to other interfaces in Agenta. For better user experience and uniformity, it's essential that the A/B testing UI aligns with the rest of the platform.

In the wireframes, we also propose to show the results in this view of the evaluation. This is low priority.

Describe the solution you'd like

• UI Consistency: Update the A/B testing UI to match the design patterns, styles, and layouts of other Agenta UIs.
• Additional Feature: As depicted in the provided wireframe, introduce a feature to show evaluation results within this view. This enhancement, while useful, is considered of lower priority and can be addressed in a subsequent update.