fix labels on ERDDAP images

[7yl4r]

• [x] VIIRS chlor_a: label on images from ERDDAP say VIIRS Kd490 on 2nd line
• [x] VIIRS SSTN: label looks ok
• [x] MODIS ABI: label looks ok
• [x] VIIRS Rrs_671: label on images from ERDDAP say VIIRS Kd490 on 2nd line
• [x] VIIRS Kd490: label looks ok

[7yl4r]

I think the issue here is a bad title or other value in datasets.xml