MinItems and MaxItems validations

[jbardin]

This PR is reduced in scope from #22484, only removing the validation that we cannot reliably handle. The dedicated Validated method contained a lot of duplicated logic, and added minimal value in the validation process (types and structure should match at this point), only really being able to catch MaxItems validations at the last moment.

We can evaluate if Validate has a use in this are later on, or if full validation should simply be under the purview of the value recipient which will have other constraint checks anyway. Making better use of InternalValidate can also be decided separately from this change.

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Due to both the nature of dynamic blocks, and the need for resources to
sometimes communicate incomplete values, we cannot validate MinItems and
MaxItems in CoerceValue. While most of the checks were removed already, the
NestingSingle, NestingGroup blocks were still being checked.

During decode, we can only validate MinItems >= 1 (equiv to "Required"),
as dynamic blocks each only decode as a single block. MaxItems
cannot be validated at all, also because of dynamic blocks, which may
have any number of blocks in the config.

Fixes #22414

[mildwonkey]

looks reasonable to me!

[ghost]

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