Fail gracefully if we can't set up code tour

We're running this at the extension start-up. We don't want it to block the extension
from completing activation, so let's swallow any errors from the code tour and output
them, instead of letting this affect the rest of the extension activation.

extensions/ql-vscode/src/extension.ts

@@ -345,7 +345,13 @@ export async function activate(
     codeQlExtension.variantAnalysisManager,
   );
 
-  await prepareCodeTour();
+  try {
+    await prepareCodeTour();
+  } catch (e: unknown) {
+    console.log(
+      `Could not open tutorial workspace automatically: ${getErrorMessage(e)}`,
+    );
+  }
 
   return codeQlExtension;
 }