Added error when Enum member initialiser references itself

[acutmore]

Emits a Property_0_is_used_before_being_assigned error when an Enum member has an initaliser that references itself.

I was not sure if this warranted added a new error message, or alternatively adapting ts(2651): A member initializer in a enum declaration cannot reference members declared after it, including members defined in other enums.

enum E {
   a = E.a // error E.a will be undefined
}

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Fixes #34606

[msftclas]

All CLA requirements met.