Create Unit tests for Update-* functions

[jaapbrasser]

There are currently no unit tests for these functions, proper unit tests should be written for these functions so we can make this part of the CI/CD pipeline. This will provide more confidence when writing additional functionality or fixing bugs in the module.

Unit tests should be created for the following functions:

• Update-RubrikHost
• Update-RubrikVCenter

Describe alternatives you've considered

Manually testing function when adding functionality