fix: resolve QStringBuilder type mismatch in ternary operator

[SD191100]

Description

Fixes a compilation failure occurring under explicit compilation configurations where QT_USE_QSTRINGBUILDER is enforced.

Problem

At line 837 in src/utils/folderutils.cpp, a ternary conditional operator (? :) evaluates an empty string literal (const char*) on the left branch, and a concatenated QString expression on the right branch. Under QT_USE_QSTRINGBUILDER optimizations, the right-hand expression evaluates as a lazy QStringBuilder template type. Because C++ strict type resolution requires uniform type yields across both conditional evaluation paths, the compiler throws a fatal initialization error due to type mismatch.

The Solution

Explicitly returned an optimized, default-constructed QString("") on the true branch evaluation block to satisfy type parity across compiler configurations.

note: This is my very first Pull Request to an open-source project. If there are any project-specific formatting preferences, commit linting styles, or documentation guidelines I missed, please let me know

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[KjellMorgenstern]

The change itself seems trivial, I'll include it for 1.0.8. The main question remainig is, why enforce QT_USE_QSTRINGBUILDER ? Is there any issue without it, did you run any measurements?