Fix Mirador build process on main. Similar to "build:prod" it needs to use "cross-env" to work with later versions of Node (especially v22.20+)

(cherry picked from commit 8f2562b)

Author: tdonohue

package.json

@@ -38,7 +38,7 @@
     "clean:prod": "npm run clean:dist && npm run clean:log && npm run clean:doc && npm run clean:coverage && npm run clean:json",
     "clean": "npm run clean:prod && npm run clean:dev:config && npm run clean:cli && npm run clean:node",
     "sync-i18n": "ts-node -r tsconfig-paths/register --project ./tsconfig.ts-node.json scripts/sync-i18n-files.ts",
-    "build:mirador": "webpack --config webpack/webpack.mirador.config.ts",
+    "build:mirador": "cross-env TS_NODE_PROJECT=./tsconfig.ts-node.json webpack --config webpack/webpack.mirador.config.ts",
     "merge-i18n": "ts-node -r tsconfig-paths/register --project ./tsconfig.ts-node.json scripts/merge-i18n-files.ts",
     "cypress:open": "cypress open",
     "cypress:run": "cypress run",