MM-59934: Add Redis to CI and other improvements (#28164)

- Update library version.
- Added MaxFlush delay to help reduce CPU usage.
- Fall back to LRU cache for the caches which use SCAN.
- Added mattermost-redis and running for all api layer
tests in Postgres.

https://mattermost.atlassian.net/browse/MM-59934
```release-note
NONE
```

server/channels/api4/metrics_test.go

@@ -30,6 +30,7 @@ func setupMetricsMock() *mocks.MetricsInterface {
 	metricsMock.On("IncrementHTTPError").Return()
 	metricsMock.On("IncrementHTTPRequest").Return()
 	metricsMock.On("ObserveAPIEndpointDuration", mock.AnythingOfType("string"), mock.AnythingOfType("string"), mock.AnythingOfType("string"), mock.AnythingOfType("string"), mock.AnythingOfType("string"), mock.AnythingOfType("float64")).Return()
+	metricsMock.On("ObserveRedisEndpointDuration", mock.AnythingOfType("string"), mock.AnythingOfType("string"), mock.AnythingOfType("float64")).Return()
 	metricsMock.On("Register").Return()
 
 	return metricsMock