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/public/model/config.go

@@ -935,27 +935,32 @@ func (s *ServiceSettings) SetDefaults(isUpdate bool) {
 }
 
 type CacheSettings struct {
-	CacheType     *string `access:",write_restrictable,cloud_restrictable"`
-	RedisAddress  *string `access:",write_restrictable,cloud_restrictable"` // telemetry: none
-	RedisPassword *string `access:",write_restrictable,cloud_restrictable"` // telemetry: none
-	RedisDB       *int    `access:",write_restrictable,cloud_restrictable"` // telemetry: none
+	CacheType          *string `access:",write_restrictable,cloud_restrictable"`
+	RedisAddress       *string `access:",write_restrictable,cloud_restrictable"` // telemetry: none
+	RedisPassword      *string `access:",write_restrictable,cloud_restrictable"` // telemetry: none
+	RedisDB            *int    `access:",write_restrictable,cloud_restrictable"` // telemetry: none
+	DisableClientCache *bool   `access:",write_restrictable,cloud_restrictable"` // telemetry: none
 }
 
 func (s *CacheSettings) SetDefaults() {
 	if s.CacheType == nil {
-		s.CacheType = NewString(CacheTypeLRU)
+		s.CacheType = NewPointer(CacheTypeLRU)
 	}
 
 	if s.RedisAddress == nil {
-		s.RedisAddress = NewString("")
+		s.RedisAddress = NewPointer("")
 	}
 
 	if s.RedisPassword == nil {
-		s.RedisPassword = NewString("")
+		s.RedisPassword = NewPointer("")
 	}
 
 	if s.RedisDB == nil {
-		s.RedisDB = NewInt(-1)
+		s.RedisDB = NewPointer(-1)
+	}
+
+	if s.DisableClientCache == nil {
+		s.DisableClientCache = NewPointer(false)
 	}
 }
 
@@ -4507,6 +4512,10 @@ func (o *Config) Sanitize(pluginManifests []*Manifest) {
 		*o.ServiceSettings.SplitKey = FakeSetting
 	}
 
+	if o.CacheSettings.RedisPassword != nil {
+		*o.CacheSettings.RedisPassword = FakeSetting
+	}
+
 	o.PluginSettings.Sanitize(pluginManifests)
 }