fix(ui): prevent NaN aspect ratio in createThumbnail on svg files

[akhrarovsaid]

What?

This PR fixes an issue for Firefox users encountered when drag-and-dropping an svg file into the BulkUpload drawer dropzone where, because of both img.width and img.height being 0, aspect ratio becomes NaN due to division by zero.

Why?

To prevent a runtime error for Firefox users and to render an appropriate thumbnail as expected.

How?

By logically checking that the divisor, in this case img.height is not zero, and setting a fallback if so.

Notes:

• This is a follow-up to an issue I found while authoring fix(ui): remove clearData call in dropzone drop handler #10475 which shows up as a runtime error in the below videos as well.
• As a result of this PR, I was reminded of another bug where thumbnails were not correctly updated if the BulkUpload EditForm contained only some successful files saved.

Before:
https://github.com/user-attachments/assets/e1b12a55-551a-4fcb-9df7-dabde87729b6

After:
https://github.com/user-attachments/assets/52791919-b657-4580-ac37-ca4be749c9a7