fix: OMUrl path in examples outdated

[vincentvdwal]

Suggested new OM File structure:

const omUrl = `https://map-tiles.open-meteo.com/data_spatial/dwd_icon/%latest%/%current+1H%.om?variable=temperature_2m`;

with /%latest%/ and /%in-progress%/ as model run options

and /%current%/ and /%valid_times_{index}%/ for the timestep options

where /%current%/ also accepts a modifier like +1H or +1D