Parse `OwnedLazyValue` into a custom struct

[themanforfree]

Is your feature request related to a problem? Please describe.

For Value, we can use sonic_rs::from_value to parse it into a custom struct.
For LazyValue, we can use LazyValue::as_raw_str to access raw str, than use sonic_rs::from_str to parse it into a custom struct.
But for OwnedLazyValue, I don't know how to parse it into a custom struct. In version 0.3, I can also use as_raw_str to process it, but the current version does not have this method.

Describe the solution you'd like
maybe like this

    let foo: Foo = Foo::deserialize(owned_lazy_value)?;

[liuq19]

could use to_string at first and use from_str to Value

[themanforfree]

could use to_string at first and use from_str to Value

This incurs additional serialization overhead and heap allocations, which I would like to avoid

[liuq19]

we donot have time to support to_value for OwnedLazyValue