Fix the permission error in Wave tour containerized version when run as a nonroot user

#### Wave SDK Version, OS

Error come from v1.5.1

#### Actual behavior

ERROR: Traceback (most recent call last):
File "/app/venv/lib/python3.10/site-packages/starlette/routing.py", line 693, in lifespan async with self.lifespan_context(app) as maybe_state:
File "/app/venv/lib/python3.10/site-packages/starlette/routing.py", line 569, in __aenter__ await self._router.startup()
File "/app/venv/lib/python3.10/site-packages/starlette/routing.py", line 670, in startup await handler()
File "/app/examples/tour.py", line 374, in on_startup os.mkdir(tour_tmp_dir) PermissionError: [Errno 13] Permission denied: '/app/examples/_tour_apps_tmp' ERROR: Application startup failed.

#### Expected behavior

Should be able to open the app without permission error.

#### Steps To Reproduce

1. Do this
2. Do that
3. Do something else
4. See error

Start at examples/tour.py line 374, where startup creates /app/examples/_tour_apps_tmp, and reproduce the container as a nonroot user. Determine how that directory should be made writable without causing the permission error, then verify that the application opens successfully during startup.

Written by the indexing model from the issue text.