ATOM-15266 [RHI][Vulkan][Android] Use warning on fragment pool error due to recreation of the memory pool in subsequent step

JIRA: https://jira.agscollab.com/browse/ATOM-15266

Gems/Atom/RHI/Vulkan/Code/Source/RHI/DescriptorSet.cpp

@@ -239,7 +239,16 @@ namespace AZ
                 allocInfo.pSetLayouts = &nativeLayout;
 
                 VkResult result = vkAllocateDescriptorSets(descriptor.m_device->GetNativeDevice(), &allocInfo, &m_nativeDescriptorSet);
-                AssertSuccess(result);
+                if (result == VK_ERROR_FRAGMENTED_POOL)
+                {
+                    // fragmented pool will be re-created subsequently, so warning only 
+                    AZ_Warning("Vulkan RHI", false, "Fragmented pool");
+                }
+                else 
+                {
+                    AssertSuccess(result);
+                }
+
                 if (result != VK_SUCCESS)
                 {
                     return result;

Gems/Atom/RHI/Vulkan/Code/Source/RHI/Vulkan.cpp

@@ -96,6 +96,8 @@ namespace AZ
                 return "Validation failed";
             case VK_ERROR_OUT_OF_POOL_MEMORY:
                 return "Pool is out of memory";
+            case VK_ERROR_FRAGMENTED_POOL:
+                return "Fragmented pool";
             default:
                 return "Unknown error";
             }