fix: add content example resolving for request bodies and parameters

[jacobps1]

Description

• Fixes content example resolving for request bodies and parameters.
• Refactors duplicate content resolution logic (schema + examples) into a shared resolveContent() helper method.

Fixes: #2292

Type of Change

• 🐛 Bug fix
• ✨ New feature
• ♻️ Refactor (non-breaking change)
• 🧪 Tests
• 📝 Documentation
• 🧹 Chore (build or tooling)

Checklist

• I have added/updated tests as needed
• I have added/updated documentation where applicable
• The PR title is descriptive
• The code builds and passes tests locally
• I have linked related issues (if any)

[jacobps1]

Tagging @ewaostrowska and @daniel-kmiecik since I see you last contributed to this file. Let me know if there is someone else I should tag!