Android app creating duplicate files when uploading

### Describe the bug
When uploading a file using the browser uploader, if the file already exists on the server, it's ignored; an additional file is only created when the files are different, but the filenames are the same.
The android app doesn't have this behavior, and instead always creates an additional file with a changed name, even then that file already exists on the server.
### To Reproduce
Upload the same file twice using the android app

### Expected behavior
Copyparty detects that the file hash already exists, and doesn't create a new file.

### Server details (if you're NOT using docker/podman)
* **server OS / version:**
win11
* **what copyparty did you grab:**
sfx
* **how you're running it:**
in a terminal
* run copyparty with `--version` and grab the last 3 lines (they start with `copyparty`, `CPython`, `sqlite`) and paste them below this line:
copyparty v1.19.0 "usernames" (2025-08-07)
CPython v3.13.0 on Windows64 10.0.26100 [MSC v.1941 64 bit (AMD64)]
sqlite 3.45.3*1 | jinja 2.11.3 | pyftpd 1.5.10 | tftp 0.4.0
* **copyparty arguments and/or config-file:**
global arguments `e2dsa, e2ts, dedup, z, chpw, qr`

### Client details
* the device type and model: Galaxy S10
* OS version: Android 12
* app version: 1.7.0