CacheInputEntryStream escapes the value for every byte in the value

The CacheEntryInputStream calls to escape the value for every single byte https://github.com/infinispan/infinispan/blob/7b84b0871d6256aaeb7311cbefb8a3a11139e3b1/server/rest/src/main/java/org/infinispan/rest/CacheEntryInputStream.java#L189

This is a simple fix to just use the currentValue field instead as it already escaped it.