[SIS-xxx] updating abstracto version to 1.5.51

adjusting template names to not use a locale

templates/sissi-templates/template-overrides/experience-template-overrides/src/main/resources/default/listener/experienceTrackerListener/experience_level_up_notification_embed.ftl

@@ -2,6 +2,5 @@
     <#assign userMention=memberDisplay.memberMention>
     <#assign pastLevel=oldLevel>
     <#assign currentLevel=newLevel>
-    <#setting locale="de_DE">
     "additionalMessage": "<@safe_include "experience_level_up_notification_text"/>"
 }

templates/sissi-templates/template-overrides/logging-template-overrides/src/main/resources/default/listener/user_joined/user_join_embed.ftl

@@ -1,6 +1,5 @@
 {
         <#assign userMention>${member.asMention}</#assign>
         <#assign user>${member.user.name} (${member.asMention}: ${member.id})</#assign>
-        <#setting locale="de_DE">
         "additionalMessage": "<@safe_include "user_joined_text"/>"
 }

templates/sissi-templates/template-overrides/logging-template-overrides/src/main/resources/default/listener/user_left/user_leave_embed.ftl

@@ -1,6 +1,5 @@
 {
     <#include "user_detail">
     <#assign user><@user_detail user=user/></#assign>
-    <#setting locale="de_DE">
     "additionalMessage": "<@safe_include "user_left_text"/>"
 }