PR: Ensure that thecolour.utilities.as_float definition do not reduce dimensionality

[KelSolaar]

Summary

This PR ensures that the colour.utilities.as_float definition do not reduce dimensionality. We piggy backed on some of its behaviour but it is inconsistent and caused issues when processing 1-pixel images.

References #1188.

Preflight

Code Style and Quality

• Unit tests have been implemented and passed.
• Pyright static checking has been run and passed.
• Pre-commit hooks have been run and passed.
• [N/A] New transformations have been added to the Automatic Colour Conversion Graph.
• [N/A] New transformations have been exported to the relevant namespaces, e.g. colour, colour.models.

Documentation

• [N/A] New features are documented along with examples if relevant.
• [N/A] The documentation is Sphinx and numpydoc compliant.

[coveralls]

coverage: 99.775%. remained the same when pulling 58628e4 on feature/dimensionality_reduction into 708ded0 on develop.