Fix UIAElement.setValueByType

iOS tests sometimes fail with because the typing is too fast and keys get out of sync, particularly when shifted. The solution is to send each key individually, rather than through `sendKeysToActiveElement`. Also, on error, we should retry the key once.
i think we still want to avail ourselves of the logic in `sendKeysToActiveElement`, which sometimes uses `typeString` under the hood and sometimes uses `typeKey`, to handle special characters. or we could maybe just use `typeKey` here which might work well for both cases