fix(lib): Fix MIME type exclusion condition

As `mime.extension()` returns `false`, instead of `null` or `undefined`,
this condition simply needs to check for truthyness.

Change-type: patch

lib/shared/supported-formats.js

@@ -40,7 +40,7 @@ exports.getCompressedExtensions = () => {
   for (const [ mimetype, cls ] of sdk.sourceDestination.SourceDestination.mimetypes.entries()) {
     if (cls.prototype instanceof sdk.sourceDestination.CompressedSource) {
       const extension = mime.extension(mimetype)
-      if (extension !== null) {
+      if (extension) {
         result.push(extension)
       }
     }