refactor(info_messages): Remove Mailgun alert

This commit refactors the `info_messages.sh` module by removing the Mailgun (email) alert functionality. The code changes remove the corresponding section that displays the Mailgun alert status in the info message script. This change simplifies and streamlines the code by eliminating unused functionality.

lgsm/modules/info_messages.sh

@@ -506,7 +506,6 @@ fn_info_message_script() {
 	# Email alert:            off
 	# Gotify alert:           off
 	# IFTTT alert:            off
-	# Mailgun (email) alert:  off
 	# Pushbullet alert:       off
 	# Pushover alert:         off
 	# Rocketchat alert:       off
@@ -550,8 +549,6 @@ fn_info_message_script() {
 		echo -e "${lightblue}Gotify alert:\t${default}${gotifyalert}"
 		# IFTTT alert
 		echo -e "${lightblue}IFTTT alert:\t${default}${iftttalert}"
-		# Mailgun alert
-		echo -e "${lightblue}Mailgun (email) alert:\t${default}${mailgunalert}"
 		# Pushbullet alert
 		echo -e "${lightblue}Pushbullet alert:\t${default}${pushbulletalert}"
 		# Pushover alert