errcheck issues fixed (#29061)

Co-authored-by: Ben Schumacher <ben.schumacher@mattermost.com>

server/.golangci.yml

@@ -133,7 +133,6 @@ issues:
         channels/app/plugin_api_tests/manual.test_http_hijack_plugin/main.go|\
         channels/app/plugin_api_tests/manual.test_serve_metrics_plugin/main.go|\
         channels/app/plugin_api_tests/test_update_user_auth_plugin/main.go|\
-        channels/app/plugin_health_check_test.go|\
         channels/app/plugin_install.go|\
         channels/app/plugin_requests.go|\
         channels/app/plugin_signature.go|\

server/channels/app/plugin_health_check_test.go

@@ -78,7 +78,8 @@ func TestHealthCheckJob(t *testing.T) {
 	require.Equal(t, model.PluginStateFailedToStayRunning, env.GetPluginState(id))
 
 	// Activated manually, plugin should stay active
-	env.Activate(id)
+	_, _, err = env.Activate(id)
+	require.NoError(t, err)
 	job.CheckPlugin(id)
 	bundles = env.Active()
 	require.Equal(t, 1, len(bundles))