[BUG] `npm install --save-exact` doesn't work in 7.7.0

Current Behavior:

npm install --save-exact <package> adds save-prefix to package.json in v7.7.0.

I have tracked it down to the removal of lib/utils/flat-options.js (lines 166-167 in particular are important to this issue). I believe this file was removed and is intended to be replaced with the unified config library. This conditional setting of savePrefix needs to be handled still.

Expected Behavior:

npm should save the exact version. No prefix should be added to package.json.

Steps To Reproduce:

1. npm i -g npm@7.7.0
2. npm init -y
3. npm install --save-exact typescript@4.2.3
4. Note in package.json that typescript is ^4.2.3

Environment:

• OS: Manjaro 21.0
• Node: 10.24.0
• npm: 7.7.0

[ruyadorno]

fixed in npm@7.7.1