[Suggestion] Should show a "no dependency found" info after user search with no existed dependency

[SunnyChen1]

To Reproduce Steps to reproduce the behavior:

1. F1 to open command palette
2. Select maven: add dependency
3. Input any character(e.g.: abc) to search
4. Observe, no any info display to user

Expected behavior Should show a "no dependency found" info after user search with no existed dependency

Environments (please complete the following information as much as possible):

• OS: Windows 10
• VS Code version: 1.55.0
• Extension version 0.29.0&Old version

Screenshots