[Workspace]Hide create workspace button in workspace menu and workspace list

[wanglam]

Is your feature request related to a problem? Please describe.

This is a feature request. Only dashboard admin can create workspace, all the create workspace buttons should be hidden or show "contact to dashboard admin" to create workspace. The workspace menu and workspace list show create workspace for non dashboard admin. That is not as expected.

Describe the solution you'd like

Currently, the isDashboardAdmin will be stored in the capabilities service as dashboards.isDashboardAdmin. The front end page should read this flag to determine wether create workspace button should be displayed.

Describe alternatives you've considered

N/A

Additional context

#4944
#6389

[SuZhou-Joe]

closed because of #7357