Update send arrow color when prompt text is present

[bvvangelov]

Fixes #462554751

Change arrow to color (in both magic wand and prompt box) Send arrow should be BLACK when a user types something in

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[paullewis]

Is there any way we can take the same approach as we do here?

https://github.com/breadboard-ai/breadboard/blob/main/packages/shared-ui/src/flow-gen/flowgen-in-step-button.ts#L165-L167

Effectively we use the CSS to detect the state of the textfield and then use that to update the button.

[ggenovgoogle]

Is there any way we can take the same approach as we do here?

https://github.com/breadboard-ai/breadboard/blob/main/packages/shared-ui/src/flow-gen/flowgen-in-step-button.ts#L165-L167

Effectively we use the CSS to detect the state of the textfield and then use that to update the button.

I will refactor this as Boris is not anymore working on the project

[ggenovgoogle]

This PR can be closed, refactor is here: #7297