feat: navigation drawer item title is generated from the slide configuration

[mkobuolys]

Description

The navigation drawer item title is generated based on the following rules:

• The slide title is used if it is set in the slide configuration (FlutterDeckSlideConfiguration.title).
• If the slide title is not set, the header title is used if it is set in the slide header configuration (FlutterDeckHeaderConfiguration.title).
• The slide route is used otherwise.

Type of Change

• ✨ New feature (non-breaking change which adds functionality)
• 🛠️ Bug fix (non-breaking change which fixes an issue)
• ❌ Breaking change (fix or feature that would cause existing functionality to change)
• 🧹 Code refactor
• ✅ Build configuration change
• 📝 Documentation
• 🗑️ Chore