EVA-3995: Update validation overview doc

[apriltuesday]

Besides the diff, feel free to review the entire validation overview doc and suggest any additional changes.

[Dona094]

It looks really good!! I have a few suggestions to add to the document:

Metadata Spreadsheet section :

1. We could mention the Helper tabs of the spreadsheet

2. We could mention about the fields marked in green indicate an either/or requirement. It’s quite common for users to fill in both sections—for example, both the Novel Samples and Pre-existing Samples sections.

3. Hold Date: We could mention the Hold Date field if users want to keep the data under embargo.

Under Common Errors Seen with Metadata Checks,

1. Date fields of the metadata spreadsheet not following the YYYY-MM-DD format.

2. CV Fields: It’s very common for users to modify these fields and enter their own data

[Dona094]

Looks great!! Many thanks