Describe the bug
Autocomplete while importing packages doesn't work.

To Reproduce
Steps to reproduce the behavior:

1. Create a dart file in a flutter project.
2. Start typing import 'package:..'
3. Autocomplete doesn't show up.

Expected behavior
Auto-completion for imports should work and list all available packages.

Downgrading to 3.22.0 fixes the issue.

Screenshots (same project, same SDK versions,)

• Importing while using 3.23.0 version of the extension:

ezgif.com-gif-maker.1.mp4

• Importing while using 3.22.0 version of the extension (working as expected):

ezgif.com-gif-maker.2.mp4

Versions (please complete the following information):

• VS Code version: 1.56.2
• Dart extension version: 3.23.0
• Dart/Flutter SDK version: 2.13.0/2.2.0
• OS: Windows 10