Fix check for rzls being present (#7462)

Author: Andrew Hall

src/razor/src/razorLanguageServerOptionsResolver.ts

@@ -54,13 +54,14 @@ function findLanguageServerExecutable(withinDir: string) {
     }
 
     let pathWithExtension = `${fileName}${extension}`;
-    if (!fs.existsSync(pathWithExtension)) {
+    let fullPath = path.join(withinDir, pathWithExtension);
+
+    if (!fs.existsSync(fullPath)) {
         // We might be running a platform neutral vsix which has no executable, instead we run the dll directly.
         pathWithExtension = `${fileName}.dll`;
+        fullPath = path.join(withinDir, pathWithExtension);
     }
 
-    const fullPath = path.join(withinDir, pathWithExtension);
-
     if (!fs.existsSync(fullPath)) {
         throw new Error(
             vscode.l10n.t("Could not find Razor Language Server executable '{0}' within directory", fullPath)