feat(core): better cause data extraction

[ha1fstack]

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closes #15142

When using ExtraErrorDataIntegration, error.cause serializes with .toString() which is not very informative considering the purpose of the integration.

This PR improves error.cause handling in ExtraErrorDataIntegration by recursing the _extractErrorData for a single cause depth. To match the outer structure and provide more information the cause object is wrapped with [name].

The .toString() serialized data is gone now but if we are using LinkedErrorsIntegration the string message will still be visible.

Since these changes are useful enough, I think more detailed specifications (like cause recursion) could be addressed by future PRs - open to suggestions.

Before:

// error.cause was serialized as: "SyntaxError: bar"
{
  TypeError: {
    cause: "SyntaxError: bar"  // Just toString() output
  }
}

After:

// error.cause now includes full error data extraction
{
  TypeError: {
    cause: {
      SyntaxError: {
        baz: 42,
        foo: "aaaa...a...",
      }
    }
  }
}

[s1gr1d]

This sounds like a good idea. Thanks for submitting this