feat: use preview to compute workspace tags from terraform (#18720)

If using dynamic parameters, workspace tags are extracted using
`coder/preview`.

coderd/coderdtest/dynamicparameters.go

@@ -25,6 +25,8 @@ type DynamicParameterTemplateParams struct {
 
 	// TemplateID is used to update an existing template instead of creating a new one.
 	TemplateID uuid.UUID
+
+	Version func(request *codersdk.CreateTemplateVersionRequest)
 }
 
 func DynamicParameterTemplate(t *testing.T, client *codersdk.Client, org uuid.UUID, args DynamicParameterTemplateParams) (codersdk.Template, codersdk.TemplateVersion) {
@@ -47,6 +49,9 @@ func DynamicParameterTemplate(t *testing.T, client *codersdk.Client, org uuid.UU
 		if args.TemplateID != uuid.Nil {
 			request.TemplateID = args.TemplateID
 		}
+		if args.Version != nil {
+			args.Version(request)
+		}
 	})
 	AwaitTemplateVersionJobCompleted(t, client, version.ID)