Fix isQuickEvalCount logic

Since `false !== undefined` evaluates to true, we would assign the wrong
value to `isQuickEvalCount` when
`selectedQuery.quickEval?.quickEvalCount` is false

extensions/ql-vscode/src/run-queries-shared.ts

@@ -495,8 +495,7 @@ export async function createInitialQueryInfo(
   outputDir: QueryOutputDir,
 ): Promise<InitialQueryInfo> {
   const isQuickEval = selectedQuery.quickEval !== undefined;
-  const isQuickEvalCount =
-    selectedQuery.quickEval?.quickEvalCount !== undefined;
+  const isQuickEvalCount = Boolean(selectedQuery.quickEval?.quickEvalCount);
   return {
     queryPath: selectedQuery.queryPath,
     isQuickEval,