test: add tests for arrow function fallback behavior

[yanxue-22]

Ticket: DX-2214

This PR attempts to validate this following fix, which resolved an issue introduced by this Regression Commit.

Original Problem

The system encountered an error when parsing certain Arrow Functions with parameters (e.g., (codec) => t.array(codec)), specifically: Error: Error when parsing AdminUpdateShardKeyApiSpec: Unknown identifier codec.

Cause: The parser attempts to inline the function body for optimization. During this process, it failed because the parameters (like codec) were not recognized in the symbol table, leading to the "Unknown identifier" error.
Previous Behavior: The old code immediately returned the parsing error upon inlining failure, preventing it from checking for custom codec definitions as a necessary fallback.

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Why the Fix Works (Utilizing E.isRight Check)

The fix modifies the parser's logic to handle inlining failures gracefully, allowing it to proceed to the custom codec check:

1. Instead of immediately returning the result of parseFunctionBody(...), the code now stores the result in a variable (bodyResult).
2. It then uses an E.isRight(bodyResult) check.
   • If successful (right): The successful result is returned.
   • If it fails (left/error): The code does not return immediately. It continues execution, allowing it to reach the subsequent logic that checks for custom codec definitions.

This ensures that even if the inlining optimization fails, the parser still attempts to find a valid definition using custom codecs. Predefined codecs are found in const knownImport = project.resolveKnownImport(imp.from, imp.importedName); inside the codecIdentifier function.

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Testing the Fix

The test validates that the type parser correctly falls back to using a pre-defined custom codec for a field utilizing an arrow function with parameters (arrayFromArrayOrSingle(NonEmptyString)), ensuring it resolves to an array type without throwing an Unknown identifier codec error.