fix: Modify default description infomation on Workspaces page

Created by: fuchunlan

Signed-off-by: lannyfu lannyfu@yunify.com

What type of PR is this?

/kind bug

What this PR does / why we need it:

Which issue(s) this PR fixes:

Fixes ##kubesphere/kubesphere/3764

Special notes for reviewers:

Additional documentation, usage docs, etc.:

/assign @harrisonliu5