Switch indexes on tile client exercises

[doublebyte1]

Catchup with this PR: geopython/pygeoapi#1989

https://github.com/geopython/diving-into-pygeoapi/blob/main/workshop/content/docs/publishing/ogcapi-tiles.md
https://github.com/geopython/diving-into-pygeoapi/blob/main/workshop/exercises/html/vector-tiles.html

[ThorodanBrom]

Hello, have raised PR #193 for this