File-uploader removes previously uploaded file on cancel second upload

[thibaan]

Detailed description

Is this a feature request (new component, new icon), a bug, or a general issue?
Bug

Is this issue related to a specific component?
Yes, ibm-file-uploader

What did you expect to happen? What happened instead? What would you like to see changed?
When using the file-uploader component: if the user uploads a file, then opens the same file uploader again but cancels it, the file-uploader component sees that as a change (which is null) and removes the previously uploaded file. I expect the file changer not to go off when the user cancels the upload when there is already a file uploaded.

What browser are you working in?
Chrome

What version of the Carbon Design System are you using?
"carbon-components": "10.24.0",
"carbon-components-angular": "4.27.6",