Improve clarity on messages around missing month/day - possibly remove from displayName entirely

[emmahodcroft]

Improve error ordering and message around incomplete dates for displayName

In testing upload with some sequences, I had some without month/day. This triggers, two errors:

sampleCollectionDate: Metadata field sampleCollectionDate:'1976' - Month and day are missing. Assuming date is some time in the year.
displayName: Metadata field displayName:'1976' - Month and day are missing. Assuming January 1st.

However the order is not guaranteed (I guess this is a runtime thing?) - sometimes date appears first, sometimes display:

When sampleCollectionDate appears first, I feel it's pretty clear that we're setting the date to be 'sometime in the year'. However, when displayName appears first, it may not be clear that it's purely for the purposes of display that we are setting it to 'January 1st'.

We should ensure that sampCollDate appears first, and may want to reword the dispName one to ensure it's clear this is for naming only.

Possible alternative solution to get around problem entirely:

I'm also not 100% sure we need to be adding month-day for just displayName purposes if we don't know month and day. This seems like something we could fix without too too much effort - just add the year (or year-month)? Then we'd not have an error here at all, and would remove all possible confusion!

[theosanderson]

The display name bit should be fixed by #3567