bugfix: settings with invalid dimension should be ignore and warning should be issued

passing an invalid dimension should not treat the block as master block. the following setting should not be applied if `unknown` is not a valid dimension.

```
{
    settings: ["unknown:value"]
    some: "value"
}
```

/cc @davglass


I already did, and they all passed, but I could not understand what this block was about, can you remember?