Resolve Dependabot Item #7

[r-bartlett-gsa]

Acceptance criteria:

• [x] Dependabot item 7 is resolved: https://github.com/GSA/Challenge_gov/security/dependabot/7

[jdonis]

Work notes:

• Insecure serialization leading to RCE in serialize-javascript
• Remove transitive dependency serialize-javascript@^1.7.0, inherited from uglifyjs-webpack-plugin@2.2.0 (already deprecated)
• Remove uglifyjs-webpack-plugin and add the new plugin (terser-webpack-plugin)

Ready to test in Staging

• Correct loading of the landing page
• CSS styles, fonts, tables, and images displayed correctly
• No errors at the moment of building the portal.

[jdonis]

This change is already in PROD

[jdonis]

serialize javascript dependabot resolved PR #1407 https://github.com/GSA/Challenge_gov/pull/1407

Package.json update https://github.com/GSA/Challenge_gov/commit/43ed00a673dc3222cf56f70d743b5c09b0b6df1f#diff-a33a5dbb169fd6761423cfc0e2ab7d1ad3d39e09f28fad36f0813775b0a562b4