MM-30824: Change to idiomatic receiver names for model.SecurityBulletin (#16349)

JIRA Ticket - https://mattermost.atlassian.net/browse/MM-30824

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

model/security_bulletin.go

@@ -15,8 +15,8 @@ type SecurityBulletin struct {
 
 type SecurityBulletins []SecurityBulletin
 
-func (me *SecurityBulletin) ToJson() string {
-	b, _ := json.Marshal(me)
+func (sb *SecurityBulletin) ToJson() string {
+	b, _ := json.Marshal(sb)
 	return string(b)
 }
 
@@ -26,8 +26,8 @@ func SecurityBulletinFromJson(data io.Reader) *SecurityBulletin {
 	return o
 }
 
-func (me SecurityBulletins) ToJson() string {
-	if b, err := json.Marshal(me); err != nil {
+func (sb SecurityBulletins) ToJson() string {
+	if b, err := json.Marshal(sb); err != nil {
 		return "[]"
 	} else {
 		return string(b)