Deleting frames from a time series multi-channel stack throws exception in Fiji

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# Issue

When slicing a multi-channel time lapse tif stack using pyimagej, Fiji's default drag and drop file reader fails to open the file and throws an exception.

# Reproducing the bug

Requirements to reproduce bug:

- A multi-channel time lapse tif stack (_e.g._ my file has 3 channels and 97 frames).
- Delete time points from the data.
- Drag and drop the output file into Fiji.

This snippet will delete 5 frames from a test file and save the output.

```python
import imagej

# start pyimagej
ij = imagej.init()

# load test image
ij_img = ij.io().open('test.tif')
py_img = ij.py.from_java(ij_img)

# delete the first 5 frames
del_img = py_img[5:, :, :, :]

# write output file
out_img = ij.py.to_java(del_img)
file_name = 'test_output.tif'
ij.io().save(out_img, file_name)
```

When you drag and drop this output file into Fiji the following exception is thrown:

```
(Fiji Is Just) ImageJ 2.1.0/1.53c; Java 1.8.0_172 [64-bit]; Linux 5.8.0-41-generic; 333MB of 19573MB (1%)

java.lang.IllegalArgumentException: Unknown stack type
at ij.ImageStack.getProcessor(ImageStack.java:289)
at ij.ImagePlus.setStack(ImagePlus.java:742)
at ij.ImagePlus.(ImagePlus.java:158)
at ij.io.Opener.openTiffStack(Opener.java:809)
at ij.io.Opener.openTiff2(Opener.java:1034)
at ij.io.Opener.openTiff(Opener.java:842)
at ij.io.Opener.openImage(Opener.java:317)
at ij.io.Opener.openImage(Opener.java:243)
at ij.io.Opener.open(Opener.java:109)
at ij.io.Opener.openAndAddToRecent(Opener.java:292)
at ij.plugin.DragAndDrop.openFile(DragAndDrop.java:194)
at ij.plugin.DragAndDrop.run(DragAndDrop.java:160)
at java.lang.Thread.run(Thread.java:748)
```

Checking the `xarray` object indicates that the five frame deletion was performed successfully:

**py_img**:
```
>>> py_img

...
```

**del_img**:
```
>>> del_img

...
```

# Work arounds

There are two easy work arounds that will enable Fiji to open the pyimagej modified files.

1. Open the output image using **File** > **Import** > **Image...**.
2. Configure Fiji to use SCIFIO when openning files. **Edit** > **Options** > **ImageJ2...** and check the `Use SCIFIO when openning files (BETA!)` check box.

# Comments
Opening files using either of these two methods works great. From my inspection the output files have been edited the way I intended to.

So there's clearly something "wrong" with the output files from pyimagej that the default opener on Fiji doesn't like.

Start by running the provided pyimagej reproduction with a multi-channel time-lapse TIFF, then compare opening the saved output through Fiji's default drag-and-drop opener and the documented workarounds. Done means deleting frames still produces a TIFF that Fiji's default opener loads without an exception.

Written by the indexing model from the issue text.