🧹 Remove dead code in _enumFieldsMap

[kevmoo]

This PR addresses a dead code issue in build_cli/lib/src/enum_helpers.dart flagged by the Dart analyzer. The _enumFieldsMap function contained a trailing return null that was unreachable due to its preceding logic and the context in which it was used. I refactored the function and its public wrapper enumValueMapFromType to use non-nullable return types and explicit casting to EnumElement, as these functions are only called after the type has been verified as an enum. I also updated the primary call site in build_cli_generator.dart to reflect these changes. I've verified that the analyzer warning is resolved.

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PR created automatically by Jules for task 4810040716243885101 started by @kevmoo

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[gemini-code-assist]

Summary of Changes

Hello, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request improves code quality and type safety within the build_cli package by eliminating dead code and strengthening type guarantees. It converts nullable return types to non-nullable ones in enum-related helper functions and updates a corresponding call site, thereby resolving a Dart analyzer warning.

Highlights

• Dead Code Removal: Removed an unreachable return null statement from the _enumFieldsMap function, addressing a Dart analyzer warning.
• Type Safety Enhancement: Refactored _enumFieldsMap and enumValueMapFromType to use non-nullable return types, ensuring these functions always return a valid map or string, respectively, given their usage context.
• Explicit Type Casting: Introduced an explicit cast of targetType.element to EnumElement within _enumFieldsMap, reinforcing the assumption that the type is always an enum when this function is called.
• Call Site Update: Modified the primary call site in build_cli_generator.dart to remove the null-assertion operator (!), aligning with the new non-nullable return type of enumValueMapFromType.

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[gemini-code-assist]

Code Review

This pull request effectively removes dead code from _enumFieldsMap and improves type safety by making return types non-nullable. The changes in enumValueMapFromType and its call site in build_cli_generator.dart are consistent with this refactoring. I've added one suggestion to improve the readability of how enum constants are retrieved.

[gemini-code-assist]

For better readability and to more directly express the intent, you can use element.constants to get the enum constants instead of filtering element.fields.

Suggested change

	element.fields
	.where((p) => p.isOriginDeclaration)
	.map((p) => MapEntry(p, p.name!)),
	element.constants.map((p) => MapEntry(p, p.name!))