Incomplete `VRVulkanTextureArrayData_t` struct in c api header

[TitusKap]

There are multiple structs that use inheritance in the c++ api. Most of these are implemented in the c header by copy-pasting the members of the base struct, but for the VRVulkanTextureArrayData_t struct this seems to be missing, it only contains the two members of the derived struct seen in the c++ header.

This means that you cannot use a pointer to a VRVulkanTextureArrayData_t struct for the handle in Texture_t and to correctly submit a frame from a vulkan array image you have to define your own struct containing the 'base' members of VRVulkanTextureData_t followed by the 'derived' members of VRVulkanTextureArrayData_t and use that in the handle of the Texture_t for it to work. This does not seem intentional.