`ktx validate` fails

Hello,

Even after upgrading KTX-Software to v4.3.2 (cf #33), `ktx validate` fails:

```bash
find . -name '*.ktx2' | xargs -n1 -I{} bash -c 'echo Validating {}; ktx validate {}'
```

```
Validating ./neutral/ggx/specular.ktx2
Validating ./neutral/charlie/sheen.ktx2
Validating ./neutral/lambertian/diffuse.ktx2
Validating ./doge2/ggx/specular.ktx2
Validating ./doge2/charlie/sheen.ktx2
Validating ./doge2/lambertian/diffuse.ktx2
Validating ./helipad/ggx/specular.ktx2
Validation failed

error-6001: Mismatching dfdTotalSize and dfdByteLength. dfdTotalSize must match dfdByteLength.
dfdTotalSize is 28 but dfdByteLength is 0 and they must match.
error-6015: Invalid colorModel in basic DFD block for RGB VkFormat.
DFD block #1 colorModel in basic DFD block is KHR_DF_MODEL_UNSPECIFIED but for VkFormat VK_FORMAT_R16G16B16A16_SFLOAT it must be KHR_DF_MODEL_RGBSDA.
error-6025: Invalid sample count in basic DFD block. The sample count must match the expected sample count of the VkFormat.
DFD block #1 sample count in basic DFD block is 0 but for VkFormat VK_FORMAT_R16G16B16A16_SFLOAT it must be 4.
error-6021: Invalid bytesPlanes in basic DFD block. The values do not match the expected values.
DFD block #1 bytesPlanes in basic DFD block are 0 0 0 0 0 0 0 0 but for VK_FORMAT_R16G16B16A16_SFLOAT textures these must be 8 0 0 0 0 0 0 0.
Validating ./helipad/charlie/sheen.ktx2
Validation failed

error-6001: Mismatching dfdTotalSize and dfdByteLength. dfdTotalSize must match dfdByteLength.
dfdTotalSize is 28 but dfdByteLength is 0 and they must match.
error-6015: Invalid colorModel in basic DFD block for RGB VkFormat.
DFD block #1 colorModel in basic DFD block is KHR_DF_MODEL_UNSPECIFIED but for VkFormat VK_FORMAT_R16G16B16A16_SFLOAT it must be KHR_DF_MODEL_RGBSDA.
error-6025: Invalid sample count in basic DFD block. The sample count must match the expected sample count of the VkFormat.
DFD block #1 sample count in basic DFD block is 0 but for VkFormat VK_FORMAT_R16G16B16A16_SFLOAT it must be 4.
error-6021: Invalid bytesPlanes in basic DFD block. The values do not match the expected values.
DFD block #1 bytesPlanes in basic DFD block are 0 0 0 0 0 0 0 0 but for VK_FORMAT_R16G16B16A16_SFLOAT textures these must be 8 0 0 0 0 0 0 0.
Validating ./helipad/lambertian/diffuse.ktx2
Validating ./directional/ggx/specular.ktx2
Validating ./directional/charlie/sheen.ktx2
Validating ./directional/lambertian/diffuse.ktx2
Validating ./field/ggx/specular.ktx2
Validating ./field/charlie/sheen.ktx2
Validating ./field/lambertian/diffuse.ktx2
Validating ./pisa/ggx/specular.ktx2
Validating ./pisa/charlie/sheen.ktx2
Validating ./pisa/lambertian/diffuse.ktx2
Validating ./chromatic/ggx/specular.ktx2
Validating ./chromatic/charlie/sheen.ktx2
Validating ./chromatic/lambertian/diffuse.ktx2
Validating ./ennis/ggx/specular.ktx2
Validating ./ennis/charlie/sheen.ktx2
Validating ./ennis/charlie/charlie.ktx2
Validation failed

error-3020: Missing Data Format Descriptor.
Data Format Descriptor is mandatory but dfdByteOffset is 0 and dfdByteLength is 0.
error-3021: Invalid dfdByteOffset.
dfdByteOffset is 0 but the Data Format Descriptor must immediately follow (with 4 byte alignment) the Level Index so it must be 344.
Validating ./ennis/lambertian/outputCubeMap.ktx2
Validation failed

error-3020: Missing Data Format Descriptor.
Data Format Descriptor is mandatory but dfdByteOffset is 0 and dfdByteLength is 0.
error-3021: Invalid dfdByteOffset.
dfdByteOffset is 0 but the Data Format Descriptor must immediately follow (with 4 byte alignment) the Level Index so it must be 344.
Validating ./ennis/lambertian/diffuse.ktx2
Validating ./footprint_court/ggx/specular.ktx2
Validation failed

error-6001: Mismatching dfdTotalSize and dfdByteLength. dfdTotalSize must match dfdByteLength.
dfdTotalSize is 28 but dfdByteLength is 0 and they must match.
error-6015: Invalid colorModel in basic DFD block for RGB VkFormat.
DFD block #1 colorModel in basic DFD block is KHR_DF_MODEL_UNSPECIFIED but for VkFormat VK_FORMAT_R16G16B16A16_SFLOAT it must be KHR_DF_MODEL_RGBSDA.
error-6025: Invalid sample count in basic DFD block. The sample count must match the expected sample count of the VkFormat.
DFD block #1 sample count in basic DFD block is 0 but for VkFormat VK_FORMAT_R16G16B16A16_SFLOAT it must be 4.
error-6021: Invalid bytesPlanes in basic DFD block. The values do not match the expected values.
DFD block #1 bytesPlanes in basic DFD block are 0 0 0 0 0 0 0 0 but for VK_FORMAT_R16G16B16A16_SFLOAT textures these must be 8 0 0 0 0 0 0 0.
Validating ./footprint_court/charlie/sheen.ktx2
Validation failed

error-6001: Mismatching dfdTotalSize and dfdByteLength. dfdTotalSize must match dfdByteLength.
dfdTotalSize is 28 but dfdByteLength is 0 and they must match.
error-6015: Invalid colorModel in basic DFD block for RGB VkFormat.
DFD block #1 colorModel in basic DFD block is KHR_DF_MODEL_UNSPECIFIED but for VkFormat VK_FORMAT_R16G16B16A16_SFLOAT it must be KHR_DF_MODEL_RGBSDA.
error-6025: Invalid sample count in basic DFD block. The sample count must match the expected sample count of the VkFormat.
DFD block #1 sample count in basic DFD block is 0 but for VkFormat VK_FORMAT_R16G16B16A16_SFLOAT it must be 4.
error-6021: Invalid bytesPlanes in basic DFD block. The values do not match the expected values.
DFD block #1 bytesPlanes in basic DFD block are 0 0 0 0 0 0 0 0 but for VK_FORMAT_R16G16B16A16_SFLOAT textures these must be 8 0 0 0 0 0 0 0.
Validating ./footprint_court/lambertian/diffuse.ktx2
Validating ./papermill/ggx/specular.ktx2
Validation failed

error-6001: Mismatching dfdTotalSize and dfdByteLength. dfdTotalSize must match dfdByteLength.
dfdTotalSize is 28 but dfdByteLength is 0 and they must match.
error-6015: Invalid colorModel in basic DFD block for RGB VkFormat.
DFD block #1 colorModel in basic DFD block is KHR_DF_MODEL_UNSPECIFIED but for VkFormat VK_FORMAT_R16G16B16A16_SFLOAT it must be KHR_DF_MODEL_RGBSDA.
error-6025: Invalid sample count in basic DFD block. The sample count must match the expected sample count of the VkFormat.
DFD block #1 sample count in basic DFD block is 0 but for VkFormat VK_FORMAT_R16G16B16A16_SFLOAT it must be 4.
error-6021: Invalid bytesPlanes in basic DFD block. The values do not match the expected values.
DFD block #1 bytesPlanes in basic DFD block are 0 0 0 0 0 0 0 0 but for VK_FORMAT_R16G16B16A16_SFLOAT textures these must be 8 0 0 0 0 0 0 0.
Validating ./papermill/charlie/sheen.ktx2
Validation failed

error-6001: Mismatching dfdTotalSize and dfdByteLength. dfdTotalSize must match dfdByteLength.
dfdTotalSize is 28 but dfdByteLength is 0 and they must match.
error-6015: Invalid colorModel in basic DFD block for RGB VkFormat.
DFD block #1 colorModel in basic DFD block is KHR_DF_MODEL_UNSPECIFIED but for VkFormat VK_FORMAT_R16G16B16A16_SFLOAT it must be KHR_DF_MODEL_RGBSDA.
error-6025: Invalid sample count in basic DFD block. The sample count must match the expected sample count of the VkFormat.
DFD block #1 sample count in basic DFD block is 0 but for VkFormat VK_FORMAT_R16G16B16A16_SFLOAT it must be 4.
error-6021: Invalid bytesPlanes in basic DFD block. The values do not match the expected values.
DFD block #1 bytesPlanes in basic DFD block are 0 0 0 0 0 0 0 0 but for VK_FORMAT_R16G16B16A16_SFLOAT textures these must be 8 0 0 0 0 0 0 0.
Validating ./papermill/lambertian/diffuse.ktx2
```

Start by running the reported find/xargs command with KTX-Software v4.3.2 against the .ktx2 assets, especially the failing files under helipad, ennis, footprint_court, and papermill. Compare the failing validation messages with the affected files and determine the expected asset-level correction; done means every listed .ktx2 file passes ktx validate.

Written by the indexing model from the issue text.