Allows desktop apps to open mailto links (#4282)

* Allows desktop apps to open mailto links

* Drop webbrowser, use `open` only

* switch to that_detached

* use workspace `open`

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Co-authored-by: Jonathan Kelley <jkelleyrtp@gmail.com>

Cargo.toml

@@ -314,7 +314,6 @@ memfd = "0.6.4"
 # desktop
 wry = { version = "0.45.0", default-features = false }
 tao = { version = "0.33.0", features = ["rwh_05"] }
-webbrowser = "1.0.3"
 infer = "0.19.0"
 dunce = "1.0.5"
 percent-encoding = "2.3.1"