Bug 508404

SUMMARY
Dolphin has a new selection effect, but it has hard-coded round corners, and my application style doesn't.  It would be cool if it used the same corner radius as the rest of dolphin.

STEPS TO REPRODUCE
1. Apply a theme which does not have rounded corners
2. Select something in dolphin

OBSERVED RESULT
Selection effect has round corners

EXPECTED RESULT
Selection effect takes corner radius from the system (consistent with the rest of dolphin/kde)

SOFTWARE/OS VERSIONS
> kinfo
Operating System: openSUSE Tumbleweed 20250816
KDE Plasma Version: 6.4.4
KDE Frameworks Version: 6.17.0
Qt Version: 6.9.1
Kernel Version: 6.16.1-1-default (64-bit)
Graphics Platform: Wayland
Processors: 24 × AMD Ryzen 9 5900X 12-Core Processor
Memory: 32 GiB of RAM (31.2 GiB usable)
Graphics Processor: NVIDIA GeForce RTX 3090

ADDITIONAL INFORMATION
I think maybe this is the line: https://invent.kde.org/system/dolphin/-/commit/c1e71289082ec7416ac19c822393ea70f63d1b75#394e07a1dbd713b618a86ebe67cdcf3093d3b2e1_622_625
Thanks!