Improve build process error surfacing

[jmikrut]

Right now, errors that occur during the webpack build process are not reported correctly, and the error that is logged is Cant find the configuration file located at ${configPath}.

Even if we can indeed find the config file, this error is still thrown which is misleading.

We should surface the actual error that occurs and only report that the config can't be found if it indeed can't be found.