Fix entry file field issue

[DominikVoigt]

This PR addresses an issue that occurred when an entry was imported that contained an URL in the file field.
This could happen when an entry was imported, e.g. using the WebSearchPane or if a bibliographic database was opened that contains such an entry.

Example of the issue when such an entry was imported over the WebSearchPane:

Signed-off-by: Dominik Voigt dominik.ingo.voigt@gmail.com

• Change in CHANGELOG.md described (if applicable)
• Tests created for changes (if applicable)
• Manually tested changed features in running JabRef (always required)
• Screenshots added in PR description (for UI changes)
• Checked documentation: Is the information available and up to date? If not created an issue at https://github.com/JabRef/user-documentation/issues or, even better, submitted a pull request to the documentation repository.

[Siedlerchr]

Duplicate of #7043?

[DominikVoigt]

Oh yeah, you are right. Thanks!

[Siedlerchr]

Nontheless thanks for taking a look, maybe you can take a look at that linked PR as well to see if it catches all problems