Bug 498216

SUMMARY
When drag-and-dropping image files onto the canvas, images are imported as layers named as the translation of "Background" in the current language, instead of being named after the file name.

This doesn't happen in English.

STEPS TO REPRODUCE
1. Go to menu bar → Settings → Switch Application Language and choose a non-English language where the phrase "Background" is translated, like Traditional Chinese (繁體中文, at the bottom of the list).
2. Create a new image. (Ctrl+N then Enter)
3. Drag-and-drop an image file (from eg. Dolphin) onto the canvas and select 插入為新圖層 (Insert as new layer). This also works when dragging-and-dropping multiple images and selecting Insert Many Layers.
4. Observe how the new layer name is "背景".

5. Repeat the same process but with Krita in English: 設定 (Settings) → 切換應用程式語言 (Switch Application Language) → make the primary language English
6. Create a new image, drag and drop an image file onto the canvas, select "Insert as new layer"
7. Observe how the new layer name is the more useful filename

OBSERVED RESULT
Image files inserted as new layers are named as "Background" in the current language. In English image files inserted this way are named after their filenames.

EXPECTED RESULT
Image files inserted as new layers are always named after their filenames.

SOFTWARE/OS VERSIONS
Operating System: Arch Linux
KDE Plasma Version: 6.2.4
KDE Frameworks Version: 6.9.0
Qt Version: 6.8.1
Kernel Version: 6.6.68-1-lts (64-bit)
Graphics Platform: X11
Graphics Processor: AMD Radeon RX 460 Graphics

ADDITIONAL INFORMATION
This is due to how KisImportCatcher::Private::prettyLayerName detects if the layer has a placeholder name.