fix for "not pixel exact result with scaling-accessor if zoom is exactly 1"

[zeissmicroscopy]

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Description

When using the scaling-accessor, in some cases not pixel-accurate compositions have been found.
This PR avoids using the scaling-blit-operation if zoom is exactly 1, and therefore is giving pixel-accurate results in this case.
A unit-test which exercises on of the problematic cases is added.

Fixes # (issue)

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

running unit-tests locally, testing with CZIcmd

Checklist:

• I followed the Contributing Guidelines.
• I did a self-review.
• I commented my code, particularly in hard-to-understand areas.
• I updated the documentation.
• I updated the version of libCZI following Versioning of libCZI depending on the type of change
  • Bug fix -> PATCH
  • New feature -> MINOR
  • Breaking change -> MAJOR
• I have added tests that prove my fix is effective or that my feature works.
• New and existing unit tests pass locally with my changes.