Fix memory leak related to vertex/pixel/compute shader functions (o3de#18998) (o3de#19007)

Signed-off-by: Sidharth Moudgil <moudgils@amazon.com>
Co-authored-by: moudgils <47460854+moudgils@users.noreply.github.com>

Author: nick-l-o3de

Gems/Atom/RHI/Metal/Code/Source/RHI/PipelineState.cpp

@@ -419,6 +419,14 @@ namespace AZ
         {
             if (m_graphicsPipelineState)
             {
+                if (m_renderPipelineDesc.vertexFunction)
+                {
+                    [m_renderPipelineDesc.vertexFunction release];
+                }
+                if (m_renderPipelineDesc.fragmentFunction)
+                {
+                    [m_renderPipelineDesc.fragmentFunction release];
+                }
                 [m_renderPipelineDesc release];
                 m_renderPipelineDesc = nil;
                 [m_graphicsPipelineState release];
@@ -427,6 +435,10 @@ namespace AZ
 
             if (m_computePipelineState)
             {
+                if (m_computePipelineDesc.computeFunction)
+                {
+                    [m_computePipelineDesc.computeFunction release];
+                }
                 [m_computePipelineDesc release];
                 m_computePipelineDesc = nil;
                 [m_computePipelineState release];