Make particle emitter editor window source code button disable itself is no source code is available

Source/Engine/Particles/ParticleEmitter.cpp

@@ -440,4 +440,21 @@ bool ParticleEmitter::Save(const StringView& path)
     return SaveSurface(data);
 }
 
+bool ParticleEmitter::HasShaderCode()
+{
+    if(SimulationMode != ParticlesSimulationMode::GPU)
+    {
+        return false;
+    }
+
+    #if COMPILE_WITH_PARTICLE_GPU_GRAPH && COMPILE_WITH_SHADER_COMPILER
+    if(_shaderHeader.ParticleEmitter.GraphVersion == PARTICLE_GPU_GRAPH_VERSION
+        && HasChunk(SHADER_FILE_CHUNK_SOURCE)
+        && !HasDependenciesModified())
+        return true;
+    #endif
+
+    return false;
+}
+
 #endif