fix: prevent Test ErrorBoundary access in production mode

[roomote]

This PR fixes issue #6335 where users could access Test ErrorBoundary functionality in production builds, causing critical errors.

Problem

The exposeSourceMapsForDebugging function in sourceMapInitializer.ts was incorrectly exposing debugging functions like __testSourceMaps in production mode. This allowed users to trigger the Test ErrorBoundary functionality even after the UI button was removed, causing the error:

TypeError: Cannot read properties of undefined (reading 'nonExistentMethod')

Solution

• Fixed the condition in exposeSourceMapsForDebugging to only expose debugging functions in development mode
• Changed if (process.env.NODE_ENV !== "production") to if (process.env.NODE_ENV === "production") to return early in production
• Added comprehensive tests to verify debugging functions are not exposed in production

Testing

• Added new test file sourceMapInitializer.spec.ts with 4 test cases
• Verified debugging functions are not exposed in production mode
• Verified debugging functions are still available in development and test modes
• All existing tests continue to pass

Impact

• Prevents users from accessing Test ErrorBoundary functionality in production
• Maintains debugging capabilities in development environment
• No breaking changes to existing functionality

Fixes #6335

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Important

Fix exposeSourceMapsForDebugging to prevent exposing debugging functions in production mode and add tests to verify behavior.

• Behavior:
  • Fix exposeSourceMapsForDebugging in sourceMapInitializer.ts to prevent exposing debugging functions in production mode.
  • Change condition to if (process.env.NODE_ENV === "production") to return early in production.
• Testing:
  • Add sourceMapInitializer.spec.ts with tests verifying debugging functions are not exposed in production.
  • Ensure functions are exposed in development and test modes.
  • Verify no errors when called multiple times in production.
• Impact:
  • Prevents access to Test ErrorBoundary in production.
  • Maintains debugging in development.
  • No breaking changes.

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[daniel-lxs]

Closed by #6216