Refactor: Change usages of returned Tasks to be awaited

[hartmannr76]

Reference discussion here.

Essentially, update all usages where Task's are returned without being awaited, to await them.

Example

public Task DoThing() => return Task.Delay(1);
// should be
public async Task DoThing() => await Task.Delay(1);

Additionally, if there is a way to enforce this in a lint step, that could be investigated.