Fix unable to remove data from a submission form field of type "name"

[AbhinavS96]

Description

Adding a null check similar to the other handlers in the file. Fixes #4073

Instructions for Reviewers

List of changes in this PR:

• Additional null check in dispatchOperationsFromChangeEvent

This can be tested on a submission form that has an input of type "name". As mentioned in the issue, the "editor" field of the journal submission form is a good candidate to test this.

1. Type something in the "editor" field.
2. Save the form
3. Remove the text from the same field
4. Save the form
5. Refresh the page

The field should now be empty.

Checklist

• My PR is created against the main branch of code (unless it is a backport or is fixing an issue specific to an older branch).
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[tdonohue]

👍 Thanks @AbhinavS96 ! I've verified this fixes the reported bug. I've also verified this bug seems to affect 7.x and main as well. So, this PR should be ported to those releases (hopefully the automatic ports should work for this small PR).

[dspace-bot]

Successfully created backport PR for main:

• [Port main] Fix unable to remove data from a submission form field of type "name"  #4236

[dspace-bot]

Successfully created backport PR for dspace-7_x:

• [Port dspace-7_x] Fix unable to remove data from a submission form field of type "name"  #4237