Double encoded image urls when using SourceSetViewHelperTrait

[akiessling]

Related to #693, #1364

I have a FAL file with special chars as input for <v:media.image src="{image.id}" and srcset configuration.

When \FluidTYPO3\Vhs\Traits\SourceSetViewHelperTrait::addSourceSet runs, it already rawurlencodes the url when it calls static::preprocessSourceUri, then preprocessSourceUri runs rawurlencode again.

https://github.com/FluidTYPO3/vhs/blob/development/Classes/Traits/SourceSetViewHelperTrait.php#L52
https://github.com/FluidTYPO3/vhs/blob/development/Classes/ViewHelpers/Media/AbstractMediaViewHelper.php#L61

Result: "Lösungen" becomes "L%25C3%25B6sungen" instead of "L%C3%B6sungen".
I guess the encoding in addSourceSet should be dropped

[akiessling]

The problem was already reported in #1512 and got closed, but the issue was not fixed with the referenced change.