[MM-51854] Onboarding Role selection screen (#23121)

Co-authored-by: Mattermost Build <build@mattermost.com>

server/channels/app/onboarding_test.go

@@ -28,3 +28,21 @@ func TestOnboardingSavesOrganizationName(t *testing.T) {
 	require.NoError(t, storeErr)
 	require.Equal(t, "Mattermost In Tests", sys.Value)
 }
+
+func TestOnboardingFirstAdminRole(t *testing.T) {
+	th := Setup(t)
+	defer th.TearDown()
+
+	err := th.App.CompleteOnboarding(&request.Context{}, &mm_model.CompleteOnboardingRequest{
+		Organization: "myorg",
+		Role:         "engineering",
+	})
+	require.Nil(t, err)
+	defer func() {
+		th.App.Srv().Store().System().PermanentDeleteByName(mm_model.SystemFirstAdminRole)
+	}()
+
+	sys, storeErr := th.App.Srv().Store().System().GetByName(mm_model.SystemFirstAdminRole)
+	require.NoError(t, storeErr)
+	require.Equal(t, "engineering", sys.Value)
+}