Companion for removal of execution strategies (#7443)

* Companion for removal of execution strategies

https://github.com/paritytech/substrate/pull/14387

* Fix some tests

* 🤦

* Adapt to latest changes

* Start supporting the offchain transaction pool

* Fix tests

* FMT

* Remove patches

* Update Substrate

* update lockfile for {"substrate"}

* Fix parachain upgrade smoke test

* Fix test

* Rewrite all tests to use `MockSubstemClient`

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Co-authored-by: parity-processbot <>