NamedOp::name should always return scoped names.

[aborgna-q]

// Consider a noop operation
op: Optype = prelude::Noop.to_extension_op().into()

// This returns the fully scoped name 
assert_eq!(<op as NamedOp>::name(), "prelude.Noop");

// But the same operation on the noop definition returns something different
assert_eq!(<NoopDef as NamedOp>::name(), "Noop");

// So the name can't be used as an unique id
assert_ne!(op.name(), NoopDef.name());

Since we expect names to be used as unique identifiers for the functions, they should always include the extension ids.

[aborgna-q]

Note that this change will be a breaking release. We'll have to rely on workarounds for the current version.