update(files): Update toast for file preview (#1902)

Author: phillsatellite

common/locales/en-US/main.ftl

@@ -172,7 +172,7 @@ files = Files
     .one-file-to-upload = File to Upload 1!
     .files-to-upload = Files to Upload { $num }!
     .no-thumbnail-preview = No Thumbnail available for preview
-    .not-possible-to-preview-file = It was not possible to preview this file
+    .not-possible-to-preview-file = This file type is currently not supported in preview
     .file-already-opened = File already opened
     .directory-already-with-name = There is already a directory with this name
     .no-size-available = No size available for file: { $file }