Default projection changes when `repeat` is used with the geoshape mark

[joelostblom]

Bug Description

The default projection for geoshape marks is equalEarth since #7052:

{
  "$schema": "https://vega.github.io/schema/vega-lite/v5.json",
  "width": 500,
  "height": 300,
  "data": {
    "url": "data/world-110m.json",
    "format": {"type": "topojson", "feature": "countries"}
  },
  "mark": {"type": "geoshape", "fill": "lightgray", "stroke": "gray"}
}

Open the Chart in the Vega Editor

However, when repeat is included in the spec, the projection changes back to the old mercator default:

{
  "$schema": "https://vega.github.io/schema/vega-lite/v5.json",
  "repeat": {},
  "spec": {
    "width": 500,
    "height": 300,
    "data": {
      "url": "data/world-110m.json",
      "format": {"type": "topojson", "feature": "countries"}
    },
    "mark": {"type": "geoshape", "fill": "lightgray", "stroke": "gray"}
  }
}

Open the Chart in the Vega Editor

This should not happen; equalEarth should be the default even when repeat is used.

[joelostblom]

This also happens with concat