drop database fails most of the time because the db is in used

[llali]

• MSSQL Extension Version:
• VSCode Version:
• OS Version: RHEL

Steps to Reproduce:

1. Create a new database
2. Close mssl extension
3. Open the extension, open new sql query and connect
4. Execute "Drop database [db name]

Expected: the database should get dropped successfully since there's not any other open window accessing the database

Actual: The query failed: Cannot drop database "[db name]" because it is currently in use.

[kevcunnane]

We can look at this for the next release - we should better handle our open connections and try to ensure this works as well as it does in SSMS

[llali]

A change Karl made in sqltoolsservice should be related to this issue. I'll verify to make sure it's really fixed

[llali]

fixed in microsoft/sqltoolsservice#460