Uploading an Image resets the Dataverse Collection Theme form

What steps does it take to reproduce the issue?

• When does this issue occur?
  When editing a Dataverse collection theme and uploading an image after any unsaved change

• Which page(s) does it occurs on?
  e.g. https://demo.dataverse.org/ThemeAndWidgets.xhtml?id=1997783

• What happens?
  Uploading an image Thumbnail Image using the Upload Image File button resets the unsaved changes of other fields

• To whom does it occur (all users, curators, superusers)?
  Dataverse collection administators (Admin) or any role with EditDataverse permission.

• What did you expect to happen?
  Leave the other modification unchanged.

Which version of Dataverse are you using?
Tested on v. 6.11 build master-dd1859d (https://demo.dataverse.org)

Any related open or closed issues to this bug report?
#10194 for SPA frontend testing as not implemented in the modern UI

Screenshots:

https://github.com/user-attachments/assets/4e4f0592-aaa6-4b81-a56f-22e305a44465

• https://help.github.com/en/articles/file-attachments-on-issues-and-pull-requests**

Are you thinking about creating a pull request for this issue?
No, unfortunately.

Start at the ThemeAndWidgets.xhtml page named in the report and reproduce the issue by changing another field before using Upload Image File. Trace the form and upload handling to identify why unsaved values are reset. Done means the thumbnail uploads while other unsaved theme changes remain intact.