Chore: Differentiate the ErrOrgNotFound error messages (#64131)

* Better org not found error messages

pkg/api/admin_users.go

@@ -70,14 +70,14 @@ func (hs *HTTPServer) AdminCreateUser(c *contextmodel.ReqContext) response.Respo
 	usr, err := hs.userService.Create(c.Req.Context(), &cmd)
 	if err != nil {
 		if errors.Is(err, org.ErrOrgNotFound) {
-			return response.Error(400, err.Error(), nil)
+			return response.Error(http.StatusBadRequest, err.Error(), nil)
 		}
 
 		if errors.Is(err, user.ErrUserAlreadyExists) {
-			return response.Error(412, fmt.Sprintf("User with email '%s' or username '%s' already exists", form.Email, form.Login), err)
+			return response.Error(http.StatusPreconditionFailed, fmt.Sprintf("User with email '%s' or username '%s' already exists", form.Email, form.Login), err)
 		}
 
-		return response.Error(500, "failed to create user", err)
+		return response.Error(http.StatusInternalServerError, "failed to create user", err)
 	}
 
 	metrics.MApiAdminUserCreate.Inc()

pkg/api/admin_users_test.go

@@ -209,7 +209,7 @@ func TestAdminAPIEndpoint(t *testing.T) {
 
 				respJSON, err := simplejson.NewJson(sc.resp.Body.Bytes())
 				require.NoError(t, err)
-				assert.Equal(t, "organization not found", respJSON.Get("message").MustString())
+				assert.Equal(t, org.ErrOrgNotFound.Error(), respJSON.Get("message").MustString())
 			})
 		})
 	})