BlobDB is not compatible with secondary instances (#13371)

Summary:
There was a failed TSAN crash test run that involved BlobDB and secondary instances. ltamasi said that BlobDB is not compatible with secondary instances, so I have updated the crash test script accordingly.

Pull Request resolved: #13371

Test Plan:
I confirmed there were no blob-related parameters after running

```
python3 tools/db_crashtest.py --simple blackbox --test_secondary=1
```

Reviewed By: jowlyzhang

Differential Revision: D69193105

Pulled By: archang19

fbshipit-source-id: b545d7765928a385a792fc070c1d432d1c002b3d

tools/db_crashtest.py

@@ -1073,6 +1073,7 @@ def gen_cmd_params(args):
     if (
         not args.test_best_efforts_recovery
         and not args.test_tiered_storage
+        and params.get("test_secondary", 0) == 0
         and random.choice([0] * 9 + [1]) == 1
     ):
         params.update(blob_params)