slimmer appearance of the user interface

[Ludy87]

Description

Additional elements and the submit button are only displayed when a file is inserted into the drag & drop.

This ensures that the page is consistent and remains clear when opened.

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🕯️ pray for magdeburg 🕯️

Checklist

• [x] I have read the Contribution Guidelines
• [x] I have performed a self-review of my own code
• [ ] I have attached images of the change if it is UI based
• [ ] I have commented my code, particularly in hard-to-understand areas
• [ ] If my code has heavily changed functionality I have updated relevant docs on Stirling-PDFs doc repo
• [x] My changes generate no new warnings
• [ ] I have read the section Add New Translation Tags (for new translation tags only)

[Ludy87]

/deploypr

[github-actions[bot]]

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[Frooodle]

Not sure about this PR still... since it removes the ability to see what a operation can do I think if we were to slim the interface like this and form inputs we might need to add verbose descriptions to each feature as well

[Ludy87]

We can also introduce a "more" button