* Make sure frame examples compile for wasm
This makes sure that `frame-example` and `frame-example-offchain-worker`
compile for wasm.
This also fixes compilation for these crates. The offchain worker
example doesn't use serde-json anymore as that is too heavy and breaks
`no_std` compilation.
* Apply suggestions from code review
Co-Authored-By: Nikolay Volf <nikvolf@gmail.com>
Co-authored-by: Nikolay Volf <nikvolf@gmail.com>