Revert "Bump Go version to 1.23.6 (#30242)" (#30359)

This reverts commit acbbd4c58d.

server/public/model/client4.go

@@ -774,7 +774,7 @@ func (c *Client4) DoAPIRequestReader(ctx context.Context, method, url string, da
 		rq.Header.Set(HeaderAuth, c.AuthType+" "+c.AuthToken)
 	}
 
-	if len(c.HTTPHeader) > 0 {
+	if c.HTTPHeader != nil && len(c.HTTPHeader) > 0 {
 		for k, v := range c.HTTPHeader {
 			rq.Header.Set(k, v)
 		}

server/public/model/user.go

@@ -486,7 +486,7 @@ func (u *User) PreSave() *AppError {
 		u.Props = make(map[string]string)
 	}
 
-	if len(u.NotifyProps) == 0 {
+	if u.NotifyProps == nil || len(u.NotifyProps) == 0 {
 		u.SetDefaultNotifications()
 	}
 
@@ -536,7 +536,7 @@ func (u *User) PreUpdate() {
 		u.AuthData = nil
 	}
 
-	if len(u.NotifyProps) == 0 {
+	if u.NotifyProps == nil || len(u.NotifyProps) == 0 {
 		u.SetDefaultNotifications()
 	} else if _, ok := u.NotifyProps[MentionKeysNotifyProp]; ok {
 		// Remove any blank mention keys

server/public/model/version.go

@@ -147,8 +147,8 @@ func init() {
 	seen := make(map[string]string)
 
 	for _, version := range versions {
-		major, minor, _ := SplitVersion(version)
-		verStr := fmt.Sprintf("%v.%v.0", major, minor)
+		maj, min, _ := SplitVersion(version)
+		verStr := fmt.Sprintf("%v.%v.0", maj, min)
 
 		if seen[verStr] == "" {
 			versionsWithoutHotFixes = append(versionsWithoutHotFixes, verStr)