[EuiTourStep] passing `panelProps` prevents the beacon from rendering

Noticed by Kibana's security solution, passing `panelProps` to **EuiTourStep** overrides the emotion styles which enable the beacon.

[Code sandbox reproduction](https://codesandbox.io/s/romantic-field-i8jcn0?file=/demo.js)


https://user-images.githubusercontent.com/313125/194367566-ed16e0c1-f080-4758-b318-a6205505d12a.mov

