Revert changes introduced in #990

[colincasey]

There is an issue with the changes to prune the yarn 2 cache that, in certain situations, would cause all devDependencies to be reinstalled during the prune stage which is the opposite result of the intended fix. This can cause slug sizes to increase for customers so this PR restores the previous cache clearing behavior.

Reverts #918, GUS-W-9502576

[codingjoe]

@colincasey @joshwlewis I think this just broke our deployment.

-----> Installing dependencies
       Installing node modules
       npm ERR! `npm ci` can only install packages when your package.json and package-lock.json or npm-shrinkwrap.json are in sync. Please update your lock file with `npm install` before continuing.
       npm ERR! 
       npm ERR! Invalid: lock file's [email protected] does not satisfy [email protected]
       npm ERR! 
       
       npm ERR! A complete log of this run can be found in:
       npm ERR!     /tmp/npmcache.ZyR7S/_logs/2022-04-02T19_04_38_141Z-debug-0.log

Both files are present and unchanged in the git repo from which we deploy this app.

[colincasey]

@codingjoe this PR was to address how Yarn 2 dependencies get pruned. It should't affect npm installs.

Does the issue go away if you follow the directions in the npm ci error output?

• run npm install locally
• commit the changes to your package-lock.json

[codingjoe]

We further investigated this. We didn't change the package file or the lock. However, there was a change on NPMs package index. Peculiar error, sorry for the false alarm.