[DAR-6238][External] Allow to import annotations without pixdims, affine of plane_map

[umbertoDifa]

Problem

Some DICOM files might not have a defined pixdim value. That is the case for ultrasound images.

Solution

Gracefully handle those scenarios by printing a warning and skipping pixdim calculations.

Changelog

Fix bug blocking import for DICOMs without pixdims

[linear]

DAR-6238 BUG: Error when importing annotations w/ missing pixdim value

[DawidMyslak]

I'm reviewing the backend PR for the very first time (don't trust me), I see we're trying to build protection against missing pixdims or the plane map.

My only worry is this:
https://github.com/v7labs/darwin-frontend/blob/master/src/modules/Editor/MedicalMetadata.ts#L67

So if the metadata.medical exists on the slot, both pixdims and plane_map must be present with expected typing. We're creating a risk of errors like "Cannot read properties of undefined".

I think it would be good to default pixdims to be [1, 1, 1] and plane map to:

       plane_map = {
          [slot_name]: metadata.primary_plane || 'AXIAL',
        }