MM-62079: Using a cache prefix to isolate cache keys for each test (#30261)

```release-note
A new config setting CacheSettings.RedisCachePrefix has been added which can be used to add a prefix to all Redis cache keys.
```

server/public/model/config.go

@@ -974,6 +974,7 @@ type CacheSettings struct {
 	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
+	RedisCachePrefix   *string `access:",write_restrictable,cloud_restrictable"` // telemetry: none
 	DisableClientCache *bool   `access:",write_restrictable,cloud_restrictable"` // telemetry: none
 }
 
@@ -994,6 +995,10 @@ func (s *CacheSettings) SetDefaults() {
 		s.RedisDB = NewPointer(-1)
 	}
 
+	if s.RedisCachePrefix == nil {
+		s.RedisCachePrefix = NewPointer("")
+	}
+
 	if s.DisableClientCache == nil {
 		s.DisableClientCache = NewPointer(false)
 	}