Update other-state-attributes.mdx

[yaronuliel]

Fix docs error - wrong property in result of example code

alert should be error based on the generating code sample:

https://github.com/statelyai/docs/blob/23d3b1c2c82aa2f6100cbce4fff4159c538268d5/docs/xstate/states/other-state-attributes.mdx#L154