remove PATH manipulation from .desktop file (#8309)

* remove PATH manipulation from .desktop file

* Add note for user-local intallations

electrum.desktop

@@ -1,9 +1,10 @@
 # If you want Electrum to appear in a Linux app launcher ("start menu"), install this by doing:
 # sudo desktop-file-install electrum.desktop
+# Note: This assumes $HOME/.local/bin is in your $PATH
 
 [Desktop Entry]
 Comment=Lightweight Bitcoin Client
-Exec=sh -c "PATH=\"\\$HOME/.local/bin:\\$PATH\"; electrum %u"
+Exec=electrum %u
 GenericName[en_US]=Bitcoin Wallet
 GenericName=Bitcoin Wallet
 Icon=electrum
@@ -18,5 +19,5 @@ MimeType=x-scheme-handler/bitcoin;x-scheme-handler/lightning;
 Actions=Testnet;
 
 [Desktop Action Testnet]
-Exec=sh -c "PATH=\"\\$HOME/.local/bin:\\$PATH\"; electrum --testnet %u"
+Exec=electrum --testnet %u
 Name=Testnet mode