Add support for `M50`

### Is your device already requested?

- [x] I have searched the existing issues

### Brand

Alandcc

### Name

M50 MP3 Player

### Device code

M50

### Model

_No response_

### Device images

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### Do you own the device and would be willing to test the installer?

- [x] I own the device and am willing to test the installer on it.

### Additional context

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