Date Last Modified Field is Empty

[JacqSauer]

Describe the bug
When the full line-list is downloaded, the "Date Last Modified" (appears as "events.dateLastModified" in the downloaded sheet) is empty/contains no information

To Reproduce
Steps to reproduce the behavior:

1. Go to the portal (https://sim-dev-data.covid-19.global.health/cases)
2. Click on "Download Dataset"
3. Open the dataset once it is downloaded
4. Scroll to column W
5. See that the column is empty

Expected behavior
In #106 @aimeehan1 mentioned that external users should be able to see the date last modified (YYYY-MM-DD) when they download the full dataset or a filtered version.

Screenshots
Please see JAS 03/28/2024, image 1

Environment (please complete the following information):

• OS: windows 11 (OS build 22631.3296)
• Browser Microsoft Edge -> opened in Excel (2019)
• Version 23H2

[jim-sheldon]

Querying {"events.dateLastModified": {$ne:null}} returns 0 documents

[stanislaw-zakrzewski]

Querying {"events.dateLastModified": {$ne:null}} returns 0 documents

I think this is the issue with last modified date being in two separate places in day0case.
First: events.dateLastModified which is not being set
Second: revisionMetadata.updateMetadata.date which is being set, but the revisionMetadata is meant to be only for the internal portal usage.

We can either remove one of those of set both. I'd rather set both I think.