Desktop: improve download in install script

[tessus]

This is a follow-up PR to #11889

Some distros replaced wget with wget2, but did nor set an alias. Some others have neither installed by default, but use curl instead.
However, it is almost certain that at least one is installed.

@sudokillnine here's the PR I mentioned earlier.

This change checks for the usual suspects for downloading on the command line: wget2, wget, and curl.
If none of them are found, an error is shown and the script exits.

[tessus]

If no one objects, I'll merge tomorrow evening: 2025-03-04 18:00 EST.

[sudokillnine]

Hello Tessus,

Thank you for the update of the script, I was too busy to work on it last week.

I tested the script with curl, wget and wget2 on Debian 12 and with curl and wget2 on Fedora 41.

it works well, thanks 👍

[laurent22]

Looks good to me

[tessus]

Thanks for the review. I've been hacking bash scripts for 3 decades now, but this doesn't mean that I never make mistakes. ;-) Although I tested this change at home before opening the PR.