Problem

A user was not given a proper error message when attempting to create a workspace with an existing name.

Definition of Done

When attempting to make a conflicting workspace name, there should be an error that says this name cannot be used and why.

coder version
Coder v0.7.6-devel+4f1e9dae

Steps:

1. Login to coder portal
2. choose a template and click Create Workspace
3. Create a workspace with name: WorkspaceName1
4. Again choose a template and click Create Workspace
5. Enter workspace name as WorkspaceName1

Expected: Error message about workspace name already exists
Actual: Nothing happens even dialogue is not closed