Remove LoadNexusMonitors V1 algorithm

[sf1919]

Description of work

Removal of deprecated LoadNexusMonitors v1 algorithm.

Summary of work

LoadNexusMonitors v1 algorithm was deprecated in v3.9 (#18322). This is the removal of that algorithm and any links to it.

Part of #39011

Further detail of work

Removal of algorithm files, updating of CMake and removal of all documentation links.

To test:

• tests should pass
• Check correct files have been removed
• Check correct lines have been removed from CMake
• Check there are no further links/references to LoadNexusMonitors v1

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Reviewer

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Code Review

• Is the code of an acceptable quality?
• Does the code conform to the coding standards?
• Are the unit tests small and test the class in isolation?
• If there is GUI work does it follow the GUI standards?
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• Do the release notes conform to the release notes guide?

Functional Tests

• Do changes function as described? Add comments below that describe the tests performed?
• Do the changes handle unexpected situations, e.g. bad input?
• Has the relevant (user and developer) documentation been added/updated?

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[sf1919]

Genuine test failures