Arvados

Reported that:

1. In the process I/O panel, an input file array was displayed as "can't show" instead of rendering as expected
2. In the panel to launch a workflow, allegedly the file array input isn't usable

Need to reproduce this, add a test, and fix it if there's an issue.

The parameter "fastqfile" shows "Cannot display value".

Here's the input type:

inputs: [
{
  "default": null,
  "id": "#main/fastqfile",
  "type": [
    "null",
    {
      "items": "File",
      "type": "array" 
    }
  ]
}
]

Here's the input value:

{
"fastqfile": [
  {
   "basename": "A427.fastq.gz",
   "class": "File",
   "http://arvados.org/cwl#collectionUUID": "zzzzz-...",
   "location": "keep:.../A427.fastq.gz",
   "size": 12345
  }
]
}

The type being "null" or "file array" means it is an optional input. Do the I/O panels handle optional inputs?