Allow uploading empty files

[PVince81]

Description

Allow upload zero sized files in the web UI.
It didn't work before because there was a check for directory uploads in browsers that don't support it, the check relied on zero file size and gave false positives when uploading files with no known mime types.

Related Issue

Fixes #19116

Motivation and Context

Because people sometimes upload multiple files and have an empty file in the list, they want it to go through too.

How Has This Been Tested?

Create two local empty files "test.txt" and "test.blubb". Upload both with drag and drop and the upload dialog.
Before: test.blubb doesn't go through
After: it does!

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

Backports:

• stable8.2
• stable9
• stable9.1

Please review @SergioBertolinSG @michaelstingl @VicDeo @DeepDiver1975

[mention-bot]

@PVince81, thanks for your PR! By analyzing the annotation information on this pull request, we identified @MorrisJobke, @butonic and @luckydonald to be potential reviewers

[SergioBertolinSG]

Works 👍

[VicDeo]

👍 tested with empty files and directories

[PVince81]

I'll backport this after the releases

[PVince81]

stable9.1: #26135
stable9: #26136

I think this is not critical enough for stable8.2, so I'll leave it.

[lock]

This thread has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.