Add CLI test for activation-key copy

Adresses #1704

Test results
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@Test: Copy Activation key for all valid Activation Key name ... ok
@Test: Copy Activation key for all valid Activation Key name ... ok
@Test: Copy Activation key for all valid Activation Key name ... ok
@Test: Copy Activation key for all valid Activation Key name ... ok
@Test: Copy Activation key for all valid Activation Key name ... ok
@Test: Copy Activation key for all valid Activation Key name ... ok

Proposed
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Add cProfile-related items to .gitignore
`assertEqual` will print out the actual value returned if the assertion fails. If the actual value is "Activation key was not copied", then that will be printed. If some other error occurs, then that other error message is returned.

> I want to keep this one, as it is the actual text returned when successful.

No, you don't know that. You _think_ that that's what the server will return, and it is very likely true. But you don't really know that.