normalize-yaml: Enhance to collapse spacing

[aduth]

🛠 Summary of changes

Adds new behavior to the YAML normalization package to collapse spacing between sentences in YAML content.

Related discussion: https://gsa-tts.slack.com/archives/CEUQ9FXNJ/p1706111249614589

📜 Testing Plan

Verify that make lint_yaml is produces a successful exit code.

1. make lint_yaml
2. echo $?
3. Observe: 0

Verify that reverting included normalizations and running normalization applies the changes to collapse spaces

1. git checkout main -- config/locales
2. make normalize_yaml
3. git add config/locales
4. git status
5. Observe "nothing to commit, working tree clean"

Verify that included specs pass:

1. yarn mocha app/javascript/packages/normalize-yaml/index.spec.js