Fix accessibility issues with placeholder text in submission forms by removing placeholders #10026

Job	Run time
dspace-angular / docker-build (linux/amd64, true)	1m 26s
dspace-angular-dist / docker-build (linux/amd64, true)	9m 45s
dspace-angular / docker-build_manifest	0s
dspace-angular / docker-copy_to_dockerhub	0s
dspace-angular-dist / docker-build_manifest	0s
docker-deploy	8m 3s
dspace-angular-dist / docker-copy_to_dockerhub	0s
	19m 14s

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