Fixing walker command arguments

[CryVeck]

-f argument does not exist in current walker version (cf https://benz.gitbook.io/walker/dmenu) and was preventing walker to open

removing the -f makes walker to open as intended.

[CryVeck]

Added fix for the passphrase:

• removing "-n" to get the search / input field.
• adding "-I" for getting the input

[firecat53]

If there are inconsistencies between versions, I think we need to add some checks to see which flags to set, especially if both versions are still available in the wild. The project has gone from version 0.13.26 to version 2.11 in 3 months. Even nixpkgs-unstable still only has 0.13.26.