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 think we have strong enough unit test coverage that you can try to remove it and see what happens :wink: