[Wiki] Update test: Create the wiki home page

This test exists in create_edit_clone_push_wiki_spec.rb but needs to be cleaned up. Currently, the test uses the fabricate method to create everything and then asserts if the action was successful.

This approach is correct but not clean. The fabricate method is unnecessary from now on, as the creation for any further testing should be done using the API. Because of this, it is recommended to remove fabricate and create a fabricate_via_api method that does the same thing using the API, but do save the process of the old method to use it in this test inside the spec file.

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• Recreate the fabricate steps in the spec file
• Replace the fabricate method with fabricate_via_api
• Clean up any left overs in the resource class as well as the spec
• Separate the test from all the other tests and use the API for the rest