[BUG]: geo.fitbounds falls back to the world view when locations mix antimeridian-crossing and normal features #7943

Description

layout.geo.fitbounds defaults to 'locations' in v4 (it was false in v3). When a choropleth (or scattergeo with locations) plots several locations and at least one crosses ±180°, the auto-fit resolves to a longitude span wider than the globe, so the subplot renders the default world view instead of a fit.

Affected territories are the ones whose features cross ±180°: USA (Aleutians), RUS, FJI, NZL, ATA. USA plus neighboring countries is a very common figure. This only appears when a crossing feature is combined with non-crossing ones.

Steps to reproduce

• Be on v4.0
• Run the following snippet in Plotly devtools:

   Plotly.newPlot(gd, [{
       type: 'choropleth',
       locations: ['CAN', 'USA', 'MEX'],
       locationmode: 'ISO-3',
       z: [3, 2, 1],
       showscale: false
   }], {
       geo: { projection: { type: 'equirectangular' } },
       width: 700, height: 450
   });

• Note that the view shows the world and splits the USA up

Notes

• computeBbox returns east unwrapped past 180° for a crossing feature (USA → 172.6 … 293.0), while non-crossing features stay in negative degrees (CAN → -141.0 … -52.6)
• calcGeoJSON pushes both into one flat array and calls findExtremes, so min = -141, max = 293 → 434°
• The existing compaction helper in src/plots/geo/geo.js is unreachable here: it is skipped for any choropleth and for any trace with locations, and it operates on point longitudes rather than interval endpoints