Unify code paths of create_inherent and enter (#7137)

* Remove redundant enter call.

* Remove optionality in dispute signature checking

* Make enter_inner and create_inherent the same.

* Remove redundant metric.

* Unification: enter and create_inherent.

* Remove `enter_inner` function.

* Remove dead code.

* Remove redundant import.

* Remove dead code in disputes.

* ".git/.scripts/commands/bench/bench.sh" runtime polkadot runtime_parachains::paras_inherent

* ".git/.scripts/commands/bench/bench.sh" runtime kusama runtime_parachains::paras_inherent

* ".git/.scripts/commands/bench/bench.sh" runtime westend runtime_parachains::paras_inherent

* Merge fix.

* Fix tests.

* Remove obsolete comment.

* ".git/.scripts/commands/bench/bench.sh" runtime polkadot runtime_parachains::paras_inherent

* ".git/.scripts/commands/bench/bench.sh" runtime westend runtime_parachains::paras_inherent

* ".git/.scripts/commands/bench/bench.sh" runtime kusama runtime_parachains::paras_inherent

* Review remarks, fixes.

* Guide updates.

* Fmt.

* ".git/.scripts/commands/bench/bench.sh" runtime polkadot runtime_parachains::paras_inherent

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Co-authored-by: eskimor <eskimor@no-such-url.com>
Co-authored-by: command-bot <>