438426 Fix reference pasting
This MR fixes IS-438426 by checking the returned value of the colorspace dialog according to Qt's own documentation on QMessageBox.
Test Plan
Build Krita. Paste an image from Chrome and ensure that, if the colorspace assignment dialog appear, selecting "Cancel" aborts the paste.
Formalities Checklist
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I confirmed this builds. -
I confirmed Krita ran and the relevant functions work. -
I tested the relevant unit tests and can confirm they are not broken. (If not possible, don't hesitate to ask for help!) -
I made sure my commits build individually and have good descriptions as per KDE guidelines. -
I made sure my code conforms to the standards set in the HACKING file. -
I can confirm the code is licensed and attributed appropriately, and that unattributed code is mine, as per KDE Licensing Policy.