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/config_test.go

@@ -515,7 +515,7 @@ func TestUpdateConfigDiffInAuditRecord(t *testing.T) {
 	require.NotEmpty(t, data)
 
 	require.Contains(t, string(data),
-		fmt.Sprintf(`"config_diffs":[{"actual_val":%d,"base_val":%d,"path":"ServiceSettings.ReadTimeout"}]`,
+		fmt.Sprintf(`"config_diffs":[{"actual_val":%d,"base_val":%d,"path":"ServiceSettings.ReadTimeout"}`,
 			timeoutVal+1, timeoutVal))
 }