[bug] orderFrames and multi frame DICOM files

### Description
Frames in stack can not be ordered correctly after merging 2+ multi frame DICOM files

#### Steps to Reproduce
For example, take 2 US Cardio multi frame DICOM files:
```
const series = loader.data[0].mergeSeries(loader.data);
series.stack[0].prepare();
```

#### Expected Results
As a result I expect to see all frames from first file, then all frames from second file.

#### Actual Results
However, order of frames in series.stack[0].frame will look like: first frame from both file, second frame from both file...

#### Source of the problem
orderFrames function works incorrectly.
If frame.dimensionIndexValues is null, it uses frame.imagePosition or frame.instanceNumber or frame.sopInstanceUID, but only one of this three values.
When 2+ multi frame files are merged at least 2 values should be used to get correct order of frames.

### Versions
- AMI: v0.0.23dev