Add Simple Expression constraint

[lesaltzm]

Some properties that depend on ThisItem scope will have significant performance costs to async operations. We've discussed and landed on restricting the set of things that can be accessed from those properties to just sync functions, the thisitem scope, enums, and operators.

This PR is a first pass at this, but it won't be immediately exposed to customers, so we'll iterate on it.

[CarlosFigueiraMSFT]

        return new BindingConfig(

Need to pass the enforceSimpleExpressions parameter to the .ctor when cloning.

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Refers to: src/libraries/Microsoft.PowerFx.Core/Binding/BindingConfig.cs:57 in 8f2a273. [](commit_id = 8f2a273, deletion_comment = False)

[jas-valgotar]

✅ No public API change.

[CarlosFigueiraMSFT]

[jas-valgotar]

✅ No public API change.