Revert "do not use dev source maps in prod (#6007)"

This reverts commit 625205f24b.

webpack.prod.js

@@ -22,5 +22,5 @@ module.exports = merge(common, {
             __OPENMCT_ROOT_RELATIVE__: '""'
         })
     ],
-    devtool: 'source-map'
+    devtool: 'eval-source-map'
 });