Enhanced type definitions for @arcgis/core

Provides better TypeScript support for the global $arcgis.import function, than the type definition from the @arcgis/core-adapter module.

Allows you to do this in TypeScript:

const [Map, WebTileLayer] = await $arcgis.import(["@arcgis/core/Map", "@arcgis/core/layers/WebTileLayer"] as const);
const FeatureLayer = await $arcgis.import("@arcgis/core/layers/FeatureLayer");
const locateBetweenOperator = await $arcgis.import("@arcgis/core/geometry/operators/locateBetweenOperator");

Instead of this

const [EsriMap, WebTileLayer] = await window.$arcgis.import<
  [typeof __esri.Map, typeof __esri.WebTileLayer]
>(["@arcgis/core/Map", "@arcgis/core/layers/WebTileLayer"] as const);
const FeatureLayer = await window.$arcgis.import<typeof __esri.FeatureLayer>(
  "@arcgis/core/layers/FeatureLayer",
);
const locateBetweenOperator = await window.$arcgis.import<
  typeof __esri.locateBetweenOperator
>("@arcgis/core/geometry/operators/locateBetweenOperator");