Improve missing value diagnostics for built-in attributes

[TorinAsakura]

Close #86290

When an expression name matches a built-in attribute, late resolution currently reports the attribute as an unexpected value. This keeps the macro fallback for invocable macros but ignores non-macro attributes in expression position, allowing the usual E0425 missing-value diagnostic.

Adds UI coverage for a bare value, a function call, and struct field shorthand.

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