[GUI] Silence TGFileDialog error messages

[bellenot]

Silence "Can't read file attributes" with protected system files on Windows.
This addresses the following topic on the Forum:
TGFileDialog multiple "Can't read file attributes" errors on Windows

[phsft-bot]

Starting build on ROOT-performance-centos8-multicore/soversion, ROOT-ubuntu2204/nortcxxmod, ROOT-ubuntu2004/python3, mac12arm/cxx20, windows10/default
How to customize builds

[github-actions]

Test Results

    12 files      12 suites   2d 4h 58m 1s ⏱️
 2 595 tests  2 595 ✅ 0 💤 0 ❌
29 140 runs  29 140 ✅ 0 💤 0 ❌

Results for commit 99cc14b.

[vepadulano]

Since the errors are true and valid, shouldn't we keep them? Or make them more clear as in `you are trying to access a system-protected file" or something similar?

[bellenot]

Since the errors are true and valid, shouldn't we keep them? Or make them more clear as in `you are trying to access a system-protected file" or something similar?

The user complains about the error message, then I'm not sure changing the text of the message will help in this case. And the error is ENOENT, meaning the file doesn't exists, which is not necessarily true, so telling this is a system protected file is not even reflecting the reality on all OSes

[vepadulano]

Ok, I see the reasoning, thanks!