Quota display still shows when no valid quota info is parsed

[junhaoliao]

Describe the bug
Quota display still shows when no valid quota info is parsed

To Reproduce
Steps to reproduce the behavior:

1. Create a session with a host which does not have a quota assigned.
2. Open File Manager.
3. See "NaN" in the Quota display in left panel.

Expected behavior
Quota should not show when no valid quota info is parsed.

Screenshots
TBA

Desktop (please complete the following information):

• OS: Windows
• Browser [e.g. chrome, safari]: Electron
• Version [e.g. 22]: v6.4.2

Additional context
The host can find the quota command, although running it yields no output.