Security Fix: mitigate ReDOS attacks on the chat bot.

server/lib/configuration/channel/storage.ts

@@ -38,7 +38,7 @@ async function getChannelConfigurationOptions (
   const content = await fs.promises.readFile(filePath, {
     encoding: 'utf-8'
   })
-  const sanitized = await sanitizeChannelConfigurationOptions(options, channelId, JSON.parse(content))
+  const sanitized = await sanitizeChannelConfigurationOptions(options, channelId, JSON.parse(content), 'read')
   return sanitized
 }
 
@@ -262,6 +262,7 @@ function _getForbidSpecialCharsHandler (
     name: id,
     regexp,
     modifiers: 'us',
+    regexp_engine: 'regexp', // FIXME: node-re2 is not compatible with \p{Emoji} and co, so we ensure to use RegExp here
     reason: forbidSpecialChars.reason
   }
   handler.options.rules.push(rule)