Traffic tiles don't work for Japan

### This issue is for a: (mark with an `x`)
```
- [X ] bug report -> please search issues before submitting
- [ ] feature request
- [X ] documentation issue or request
- [ ] regression (a behavior that used to work and stopped in a new release)
```

### Minimal steps to reproduce
>Use TileSetID `microsoft.traffic.flow.relative`, and navigate to over Japan. Traffic flow does not appear to be available. This can be observed on a demo site (https://samples.azuremaps.com/third-party-map-controls/azure-maps-leaflet-options) as well.

### Any log messages given by the failure
> n/a

### Expected/desired behavior
>Traffic layers would load in parity with Bing or Azure maps?

### OS and Version?
> n/a

### Versions
>leaftlet v1.9.4, auzre-maps-leaflet vLatest

### Mention any other details that might be useful

Does anyone have any insight into the availability of traffic flow tiles? The tileset `microsoft.traffic.flow.relative` does not appear to support any traffic display in Japan. This looks like it can be reproduced at the Azure Maps leaflet demo site here: https://samples.azuremaps.com/third-party-map-controls/azure-maps-leaflet-options

However, there's another Azure Maps demo site (https://demo.azuremaps.com/) that _does_ appear to have map tiles for Japan traffic. That said, inspecting the traffic calls there show a TileSetID of `microsoft.core.vector.traffic` and/or `microsoft.core.raster.traffic`. If I plug `microsoft.core.raster.traffic` into the azure-maps-leaflet tilesetId value, I do get traffic tiles, worldwide. However, they don't appear to exactly match the Azure Maps demo site. I.e., if I zoom over Chicago, the Azure Maps demo will show slowdowns, same with `microsoft.traffic.flow.relative`. But inside leaflet, the raster.traffic tileset as far as I can tell is always green for me.

I also can't find any documentation anywhere about what the `microsoft.core.*.traffic` TileSetIDs are - every Azure Maps SDK documentation I find mentions those tilesets listed here on this page. Do any of the maintainers know which is which is and which tileset should be correct and used? And if it's the ones documented here, any known issues why Japan traffic doesn't seem to exist?