Layer Settings need a way to validate `VkLayerSettingEXT`

Brought up in https://github.com/KhronosGroup/Vulkan-ValidationLayers/issues/9028

I have no good way in the Validation Layers (without me, and every other layer having to hand-write it) to make sure the `VkLayerSettingEXT` passed in from the app

1. Is not using a `pSettingName` that doesn't exists (aka, a setting was removed and they are still setting it)
2. Validate the type is correct (you try setting `INT32` of `1` or `FLOAT32` of `1.0` instead of using a `BOOL32`