Task priority labels are not internationalized with old array style

[dianabarsan]

Describe the bug
According to our documentation, task priority labels can be arrays to support translations for multiple languages. However, cht-conf schema validation requires the label to be a string.

To Reproduce

1. Create a task according to documentation.
2. Compile app settings
3. See error

ERROR tasks.js invalid schema: 
ERROR Invalid schema at tasks[3].priority.label
"priority" should be an object with optional fields "level" and "label" or a function which returns the same
Current value of tasks[3].priority.label is [{"locale":"en","content":"Home Birth"}]

Additional context
This was reported on the forum: https://forum.communityhealthtoolkit.org/t/tasks-with-medium-priority/2978

[dianabarsan]

It looks like webapp has been updated to allow for translation keys for task priority labels, with the old array format style still being supported.

[garethbowen]

We're generally moving away from arrays for labels - it makes the config complex and the translations not able to be reused. Consider just updating the documentation.