Better future handling in home view

Current issue

When launching the app, the user will land on the home view. When created the home view has this behaviour:

First, we init the state of our view.
Then, we're calling an async callback fetching the articles from the Bungie API.
Finally, we're calling a FutureBuilder with a Future<void> callback directly with the callback.

This triggers the getManifest() callback twice, making the CircularProgressIndicator appear twice in a row.

In order to comply with Flutter guidelines and to fix this unexpected behaviour, I need to follow the following guideline:

"The future must have been obtained earlier, e.g. during State.initState, State.didUpdateWidget, or State.didChangeDependencies. It must not be created during the State.build or StatelessWidget.build method call when constructing the FutureBuilder. If the future is created at the same time as the FutureBuilder, then every time the FutureBuilder's parent is rebuilt, the asynchronous task will be restarted."

This guideline states that the Future callback directly called from the build method should be created inside the initState method.

In order to fix this behaviour, I'm going to do the following:

[x] Create a Future variable.

This variable should be set as a late variable in order to be created only inside the initState method.
[x] "Combining" the 2 Future callback that I'm using by implementing the Future.wait(List) function

This function waits for the number of futures inside the future list and returns a future waiting for both callback to end.
[x] Calling my future should not display the CircularProgressIndicator loading the Manifest twice but only once