Blank dc.identifier.uri's in DSpaceMETS exports ("Duplicate blank uri's in DSpace deposits")

[laulandn]

Describe the bug
When publishing to DSpace, the deposited ETD will have an "extra" blank uri.
(Where the handle and/or doi's go).

Tracked this down to an empty dc.identifier.uri in the mets.xml file in DSpaceMETS exports zips.
(This is the data that Vireo uses when publishing, which is a Sword deposit to DSpace).

<!-- dc.identifier.uri == Deposit ID, this would only be available when re-depositing -->
<dim:field mdschema="dc" element="identifier" qualifier="uri"></dim:field>
(value is missing between "><")

DSpace will (correctly) import this line, and create a uri metadata entry that is blank.

NOTE: ETD must NOT have already been published. This is because if it has been, it then has an identifier, which is correctly handled.

To Reproduce
Steps to reproduce the behavior:

Can be seen by looking at recently published ETDs in DSpace.

To see blank entry in export, which is what Vireo uses to do Sword deposits:

1. Find a mostly complete ETD in Vireo. Ones that are in "Approved" state are perfect. (Must NOT be "Published").
2. Set up filters so you have only that single ETD selected.
3. Click on "Download Export" and choose DSpaceMETS format.
4. Open the resulting submission-XXXX-XXX.zip file.
5. Inside the zip file, the mets.xml file will include a blank dc.identifier.uri as described above.

Expected behavior
If an ETD has not yet been published, it will not have a Deposit ID.
If it does not have a Deposit ID, the DSpaceMETS file should NOT include ANY dc.identifier.uri lines.
ie the comment in the mets.xml file references this, but the line below it should be completely omitted in that case.

Screenshots
Not including any as any of a real ETD would need to be redacted to the point of just being black boxes.

Additional context
Initially tested on test vireo and training dspace.
Verified by doing curl deposits by hand of resulting zip files.
Confirmed by looking at export of Approved ETD on production Vireo.

[laulandn]

NOTE: Typically DSpace will save a copy of the original .zip METS file it received during the deposit in a "SWORD" bundle for the items (which is not visible in the simple item view). This could be used to see the problem line in any previously deposited ETDs on production DSpaces. (So you don't need to do a fresh export or deposit to see it).