Excluding all folders from sync triggers 'All files were deleted on the server message' message

[HanaGemela]

Client: 2.6.0alpha2 (build 12128)
macOS: 10.14.5
Server: 10.2.1. (stable)

Steps to recreate:

1. Make sure there are no files directly in the root directory
2. Deselect all folders in the selective sync list
3. Confirm your selection

Actual result: Message that 'all files were deleted on the server'
Expected result: No message, the files are removed only locally

4. When user selects 'Keep all'

Actual result:
Checkboxes in the selective sync list are not checked
There are no icons against the files even though the account is connected to the server

[ogoffart]

PR: #7530

[HanaGemela]

Works as expected in 2.6.1-daily20191127 (build 12791), macOS 10.15.1