Try-state for Collective pallet (#13645)

* write the try_state_ function

* update tests

* update check

* fix benchmarking

* fix nonsense

* Update frame/collective/src/lib.rs

Co-authored-by: Oliver Tale-Yazdi <[email protected]>

* Update frame/collective/src/lib.rs

Co-authored-by: Oliver Tale-Yazdi <[email protected]>

* unique proposal index

* prime must be a member of the collective

* oops

* Add new checks

* use ensure

* fix

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Co-authored-by: Oliver Tale-Yazdi <[email protected]>