Use index fragment shader output when dual source blend is enabled (#4404)

* Use index fragment shader output when dual source blend is enabled

* Shader cache version bump

* Actually set DualSourceBlendEnabled to true

* Fix XML doc

---------

Co-authored-by: Ac_K <Acoustik666@gmail.com>

Ryujinx.Graphics.Shader/IGpuAccessor.cs

@@ -205,6 +205,15 @@ namespace Ryujinx.Graphics.Shader
             return false;
         }
 
+        /// <summary>
+        /// Queries dual source blend state.
+        /// </summary>
+        /// <returns>True if blending is enabled with a dual source blend equation, false otherwise</returns>
+        bool QueryDualSourceBlendEnable()
+        {
+            return false;
+        }
+
         /// <summary>
         /// Queries host about the presence of the FrontFacing built-in variable bug.
         /// </summary>