Disable file validation temporarily, because it causes data loss of some attachments when upgrading.

Thanks to xet7 !

Related https://github.com/wekan/wekan/issues/4891

models/fileValidation.js

@@ -13,6 +13,7 @@ if (Meteor.isServer) {
 export async function isFileValid(fileObj, mimeTypesAllowed, sizeAllowed, externalCommandLine) {
   let isValid = true;
 
+/*
   if (Meteor.settings.public.ostrioFilesMigrationInProgress !== "true") {
     if (mimeTypesAllowed.length) {
       const mimeTypeResult = await FileType.fromFile(fileObj.path);
@@ -45,6 +46,7 @@ export async function isFileValid(fileObj, mimeTypesAllowed, sizeAllowed, extern
       console.debug("Validation of uploaded file successful: file " + fileObj.path);
     }
   }
+*/
 
   return isValid;
 }