UI enhancement for import observers

[avasi-code4ro]

As the observer import functionality has been moved from a modal to a dedicated page there are needed some UI / frontend improvements.

FIGMA link

1. Back Button and Breadcrumbs

• Add a Back Button to navigate to the previous page.
• Add Breadcrumb Navigation to align with the design pattern used across the app for dedicated pages.

2. Drag and Drop Area Improvements

• Increase the spacing between elements within the drag-and-drop area (as in Figma) to improve visual clarity and usability.

3. "Click Here to Browse Files" as Button

• Style the "Click here to browse files" link as a button (as per the design, using purple and underlined text).
• Maintain functionality where clicking anywhere within the drag-and-drop area still triggers the file upload action.