JS: Fix imprecise condition

Author: asgerf

javascript/extractor/src/com/semmle/js/extractor/AutoBuild.java

@@ -783,7 +783,7 @@ private CompletableFuture<?> extractSource() throws IOException {
     extractTypeScript(filesToExtract, extractedFiles,
               extractors, tsconfigFiles, dependencyInstallationResult);
 
-    boolean hasTypeScriptFiles = extractedFiles.size() > 0;
+    boolean hasTypeScriptFiles = hasTypeScriptFiles(filesToExtract);
 
     // extract remaining files
     return extractFiles(