fix: Simple hosted dependencies should be inlined

[spydon]

Description

Before this fix (after moving to pubspec_parse), when we updated shared dependencies they would explicitly use the version field.

Example before this PR:

dependencies:
  flame:
    version: ^1.21.0

After this PR:

dependencies:
  flame: ^1.21.0

Type of Change

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

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