implement dispatch_as (#9934)

* implement dispatch_as

* fix

* fix

* weight for dispatch_as

* cargo run --quiet --release --features=runtime-benchmarks --manifest-path=bin/node/cli/Cargo.toml -- benchmark --chain=dev --steps=50 --repeat=20 --pallet=pallet_utility --extrinsic=* --execution=wasm --wasm-execution=compiled --heap-pages=4096 --output=./frame/utility/src/weights.rs --template=./.maintain/frame-weight-template.hbs

* fix

* Update frame/utility/src/benchmarking.rs

Co-authored-by: Alexander Theißen <alex.theissen@me.com>

* fix issues

Co-authored-by: Parity Bot <admin@parity.io>
Co-authored-by: Alexander Theißen <alex.theissen@me.com>
Co-authored-by: Shawn Tabrizi <shawntabrizi@gmail.com>