chore(ci): reuse discord send function from library

Provides more info and requires less boilerplate.

Signed-off-by: Jakub Sokołowski <jakub@status.im>

ci/Jenkinsfile.combined

@@ -1,5 +1,5 @@
 #!/usr/bin/env groovy
-library 'status-jenkins-lib@v1.8.3'
+library 'status-jenkins-lib@v1.8.6'
 
 /* Object to store public URLs for description. */
 urls = [:]
@@ -86,24 +86,10 @@ pipeline {
       archiveArtifacts('pkg/*')
     } }
     failure { script {
-      withCredentials([
-        string(
-          credentialsId: 'discord-status-desktop-webhook',
-          variable: 'DISCORD_WEBHOOK'
-        ),
-      ]) {
-        discordSend(
-          title: "${env.JOB_NAME}#${env.BUILD_NUMBER}",
-          description: """
-            CI Desktop build Failure!
-            Branch: `${GIT_BRANCH}`
-            Commit: `${GIT_COMMIT.take(8)}`
-          """,
-          link: env.BUILD_URL,
-          result: currentBuild.currentResult,
-          webhookURL: env.DISCORD_WEBHOOK
-        )
-      }
+      discord.send(
+        header: 'CI Desktop build Failure!',
+        cred: 'discord-status-desktop-webhook',
+      )
     } }
     cleanup { cleanWs() }
   }