Prevent webpack from generating source maps in production builds

[bsclifton]

Test Plan:

?? - I need help verifying how to test this. I tried npm run build-package but didn't see file in either case.

Description

Fixes #8255

Auditors: @jonathansampson, @bbondy, @bridiver

• Submitted a ticket for my issue if one did not already exist.
• Used Github auto-closing keywords in the commit message.
• Added/updated tests for this change (for new code or code which already has tests).
• Ran git rebase -i to squash commits (if needed).

[bridiver]

I'm pretty sure this is not the right change to make. I don't know what the default is, but the docs say Note: With the next major version the default for -d will change to cheap-module-eval-source-map
If we don't want the source maps in the release we should leave them out when building the asar file

[bridiver]

I'd also like to see what we get in the console without any source maps at all. We don't want even less debugging info than we already have

[bsclifton]

@bridiver those are good points- I'm going to go ahead and close this PR out and we can re-assess the issue