Issues with Minimap and PixiJS 8.5.x and later

[bhousel]

We discovered that the minimap is not rendering correctly on versions of PixiJS 8.5.x and newer.
Instead of showing a zoomed out view, it just contained contents of the main map canvas.

I traced it to an issue with multiview rendering (where we tell Pixi to render to multiple canvases)
and opened pixijs/pixijs#11168 to keep track of it.

In the mean time, I added a workaround in bfce63f to the minimap code to get it rendering correctly again.
I've tested this on both WebGL and WebGPU and it seems ok.
When the upstream issue in is fixed, we can remove the workaround and close this issue.