QImg - add errorSrc prop (like placeholderSrc)

[Razvan Stoenescu]

Discussed in #16964

^{Originally posted by ShlomoCode March 4, 2024}
You can define an image that will appear when the image is loaded using a prop named placeholderSrc
But if you want to set an image that will appear when there is an error loading the image, you can only do this by using a slot and repeating all the QImg tag and its properties, to get a consistent look

I suggest adding an errorSrc prop where it will be possible to pass a path to the image that will appear when there is an error loading the main image

[Razvan Stoenescu]

Implemented in b0e2ef8