RGBA8 UNORM images in the viewer should be treated as sRGB

* This makes the pixel pick values come back sRGB decoded.

renderdoc/core/image_viewer.cpp

@@ -436,6 +436,7 @@ void ImageViewer::RefreshFile()
   rgba8_unorm.compCount = 4;
   rgba8_unorm.compType = CompType::UNorm;
   rgba8_unorm.type = ResourceFormatType::Regular;
+  rgba8_unorm.srgbCorrected = true;
 
   ResourceFormat rgba32_float = rgba8_unorm;
   rgba32_float.compByteWidth = 4;