Add axis labels to model size dimensions

[evanwurden]

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What does this PR do and why is it necessary?

This is a simple change to address #4866 by adding dimension axes (X,Y,Z) to the "Model Dimensions" section in additional file data. This makes it clear which dimension is associated with which axis.

How was it tested? How can it be tested by the reviewer?

Ran this on my development instance and everything works as expected, along with unit tests.

Any background context you want to provide?

N/A

What are the relevant tickets if any?

#4866

Screenshots (if appropriate)

Further notes

[foosel]

Looks good, thank you! 👍