Direct method of BlockOperator returns a single DataContainer if the output shape is (1,1)

[MargaretDuff]

Changes

See #1455

Testing you performed

Please add any demo scripts to https://github.com/TomographicImaging/CIL-Demos/tree/main/misc

Related issues/links

Fixes #1455

Checklist

• I have performed a self-review of my code
• I have added docstrings in line with the guidance in the developer guide
• I have updated the relevant documentation
• I have implemented unit tests that cover any new or modified functionality
• CHANGELOG.md has been updated with any functionality change
• Request review from all relevant developers
• Change pull request label to 'Waiting for review'

Contribution Notes

Please read and adhere to the developer guide and local patterns and conventions.

• The content of this Pull Request (the Contribution) is intentionally submitted for inclusion in CIL (the Work) under the terms and conditions of the Apache-2.0 License
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--->

[paskino]

Please add to the CHANGELOG

- Bugfix:
  - BlockOperator that would return a BlockDataContainer of shape (1,1) now return the appropriate DataContainer. BlockDataContainer direct and adjoint methods accept DataContainer as parameter x.

[samdporter]

The direct method looks good but in PR #1766 the range and domain geometries also returned a regular DataContainer if necessary. This would also be nice otherwise the range_geometry may be different to the geometry of the object returned by direct()

[MargaretDuff]