Add warning for removeConnection invoked with no selection#400

tnaum-ms merged 2 commits intodev/tnaum/connection-multi-deletemicrosoft/vscode-documentdb:dev/tnaum/connection-multi-deletefrom

copilot/sub-pr-398-againmicrosoft/vscode-documentdb:copilot/sub-pr-398-againCopy head branch name to clipboard