Propfind on empty "Share" reports no etag

```
23-02-16 17:54:42:129 [ info sync.httplogger ]: "23f27514-5606-45d2-a9e4-20ffbccb137f: Request: PROPFIND https://ocis.owncloud.test/dav/spaces/a0ca6a90-a365-4782-871e-d44447bbc668$a0ca6a90-a365-4782-871e-d44447bbc668/ Header: { Depth: 0, Prefer: return=minimal, Authorization: Bearer [redacted], User-Agent: Mozilla/5.0 (Macintosh) mirall/4.0.0-git (ownCloud, osx-22.2.0 ClientArchitecture: arm64 OsArchitecture: arm64), Accept: */*, Content-Type: text/xml; charset=utf-8, X-Request-ID: 23f27514-5606-45d2-a9e4-20ffbccb137f, Original-Request-ID: 23f27514-5606-45d2-a9e4-20ffbccb137f, Content-Length: 108, } Data: [\n]"
23-02-16 17:54:42:146 [ info sync.httplogger ]: "23f27514-5606-45d2-a9e4-20ffbccb137f: Response: PROPFIND 207 (16ms) https://ocis.owncloud.test/dav/spaces/a0ca6a90-a365-4782-871e-d44447bbc668$a0ca6a90-a365-4782-871e-d44447bbc668/ Header: { Access-Control-Allow-Origin: *, Access-Control-Expose-Headers: Tus-Resumable, Tus-Version, Tus-Extension, Content-Length: 241, Content-Security-Policy: default-src 'none';, Content-Type: application/xml; charset=utf-8, Date: Thu, 16 Feb 2023 16:54:42 GMT, Dav: 1, 3, extended-mkcol, Preference-Applied: return=minimal, Tus-Extension: creation,creation-with-upload,checksum,expiration, Tus-Resumable: 1.0.0, Tus-Version: 1.0.0, Vary: Prefer, X-Content-Type-Options: nosniff, X-Download-Options: noopen, X-Frame-Options: SAMEORIGIN, X-Permitted-Cross-Domain-Policies: none, X-Robots-Tag: none, X-Xss-Protection: 1; mode=block, } Data: [/dav/spaces/a0ca6a90-a365-4782-871e-d44447bbc668$a0ca6a90-a365-4782-871e-d44447bbc668/]"