fix: reduce the size of the commons.js asset. (#26462)

The size of commons.js has gradually grown until it is now 4 MB in
dev mode. This change brings it back down to 880 KB. This does
cause the size of some other JS assets to increase, some by as much
as 500 KB. This still seemed like a worthwhile tradeoff.

webpack.common.config.js

@@ -167,7 +167,7 @@ module.exports = Merge.smart({
                 // common/djangoapps/pipeline_mako/templates/static_content.html
                 name: 'commons',
                 filename: 'commons.js',
-                minChunks: 3
+                minChunks: 10
             })
         ],