vk_push_descriptors hits a validation error

tested commit (main today): 595e8f857cfff208f0b8dc62f18f63d12babca66

```
$ ./build/bin/vk_push_descriptors
```

```
*** VULKAN VALIDATION ERROR MESSAGE ***
Severity : ERROR
Type : [VALIDATION]
Objects : [0]:
Message : Validation Error: [ VUID-vkCmdDraw-None-02699 ] Object 0: VK_NULL_HANDLE, type = VK_OBJECT_TYPE_DESCRIPTOR_SET; | MessageID = 0x1608dec0 | Descriptor set VkDescriptorSet 0x0[] encountered the following validation error at vkCmdDraw time: Descriptor in binding #1 index 1 is being used in draw but has never been updated via vkUpdateDescriptorSets() or a similar call. The Vulkan spec states: Descriptors in each bound descriptor set, specified via vkCmdBindDescriptorSets, must be valid as described by descriptor validity if they are statically used by a bound shader (https://www.khronos.org/registry/vulkan/specs/1.3-khr-extensions/html/vkspec.html#VUID-vkCmdDraw-None-02699)
```