fix(files_versions): ensure users IDs are strings

Signed-off-by: John Molakvoæ (skjnldsv) <skjnldsv@protonmail.com>

Author: skjnldsv

apps/files_versions/src/utils/versions.ts

@@ -50,11 +50,11 @@ export async function fetchVersions(fileInfo: any): Promise<Version[]> {
 			.filter(({ mime }) => mime !== '')
 			.map(version => formatVersion(version, fileInfo))
 
-		const authorIds = new Set(versions.map(version => version.author))
+		const authorIds = new Set(versions.map(version => String(version.author)))
 		const authors = await axios.post(generateUrl('/displaynames'), { users: [...authorIds] })
 
 		for (const version of versions) {
-			const author = authors.data.users[version.author]
+			const author = authors.data.users[version.author ?? '']
 			if (author) {
 				version.authorName = author
 			}