CB-14243: change dash to underscore for save-exact key reference

[amaldonado]

Platforms affected

This affects how plugins are added for both Android and IOS.

What does this PR do?

This PR fixes CB-14243. Cordova-lib is ignoring save-exact b/c the wrong key name is being used to reference it in the options object that is propagated from cli.js.

What testing has been done on this change?

Unit tests have been run and are passing.

Checklist

✅Reported an issue in the JIRA database
✅Commit message follows the format: "CB-14243: {message}"
✅ Unit Tests pass

[brodybits]

Thanks @amaldonado for the contribution, merged it since it definitely looks right to me. A couple points of feedback:

I think it could have been done a little bit better, raised #632 with the suggestion.

This behavior is evidently not covered by the unit test suite, marking this as a major TODO item in #632.

P.S. If I would do npm i apache/cordova-lib#master in local checkout of cordova-cli then use that version to add a plugin with --save-exact flag it does save the exact plugin version in package.json & config.xml.