chore: add dry false config to CleanWebpackPlugin

[MatanBobi]

SUMMARY

After my superset/static folder reached 230Gb, I understood something is wrong with the CleanWebpackPlugin.
I've added a dry: false flag to the CleanWebpackPlugin as it must be explicitly set for the dangerouslyAllowCleanPatternsOutsideProject flag to work as written in the docs:

https://github.com/johnagan/clean-webpack-plugin/blob/master/README.md

Resolves #14690

ADDITIONAL INFORMATION

• Has associated issue:
• Changes UI - N/A
• Includes DB Migration (follow approval process in SIP-59) - N/A
  • Migration is atomic, supports rollback & is backwards-compatible - N/A
  • Confirm DB migration upgrade and downgrade tested - N/A
  • Runtime estimates and downtime expectations provided - N/A
• Introduces new feature or API - N/A
• Removes existing feature or API - N/A

CC: @amitmiran137

[villebro]

LGTM