EasyInvoice - Remove empty, gray CardHeader from CryptoToFiat component, for consistency

# Problem

Empty, gray, CardHeader on `CryptoToFiat` component is inconsistent with rest of the app.

<img width="954" alt="Image" src="https://github.com/user-attachments/assets/2458d9f2-e2d0-487f-99ea-709185e76d48" />

# Proposed Solution

Remove it.