PixelHistory UI: improve detection of depth targets

Use the same logic as TextureViewer to determine if the target is a depth target
Fixes issue of pixel history on typeless target cast to UNORM and used as depth i.e. shadow map

qrenderdoc/Windows/PixelHistoryView.cpp

@@ -58,8 +58,8 @@ public:
     m_IsSint = (compType == CompType::SInt);
     m_IsFloat = (!m_IsUint && !m_IsSint);
 
-    if(compType == CompType::Depth)
-      m_IsDepth = true;
+    m_IsDepth =
+        (m_Tex->creationFlags & TextureCategory::DepthTarget) || (compType == CompType::Depth);
 
     switch(m_Tex->format.type)
     {