Add MobileExternalBrowser to client config (#28180)

* Add MobileExternalBrowser to client config

* set config MobileExternalBrowser as a pointer

---------

Co-authored-by: Mattermost Build <build@mattermost.com>

server/public/model/config.go

@@ -2764,6 +2764,7 @@ type NativeAppSettings struct {
 	AppDownloadLink        *string  `access:"site_customization,write_restrictable,cloud_restrictable"`
 	AndroidAppDownloadLink *string  `access:"site_customization,write_restrictable,cloud_restrictable"`
 	IosAppDownloadLink     *string  `access:"site_customization,write_restrictable,cloud_restrictable"`
+	MobileExternalBrowser  *bool    `access:"site_customization,write_restrictable,cloud_restrictable"`
 }
 
 func (s *NativeAppSettings) SetDefaults() {
@@ -2782,6 +2783,10 @@ func (s *NativeAppSettings) SetDefaults() {
 	if s.AppCustomURLSchemes == nil {
 		s.AppCustomURLSchemes = GetDefaultAppCustomURLSchemes()
 	}
+
+	if s.MobileExternalBrowser == nil {
+		s.MobileExternalBrowser = NewPointer(false)
+	}
 }
 
 type ElasticsearchSettings struct {