FIX pyrit initializer config in ARM templates must be comma-separated

[behnam-o]

In startup.sh, the initializers passed in an env var are expected to be comma-separated, but in our ARM templates, they are not. This causes crashes like this when for the container app:

Connecting to stream...
2026-06-08T18:23:32.50309  Connecting to the container 'pyrit-gui'...
2026-06-08T18:23:32.61244  Successfully Connected to container: 'pyrit-gui' [Revision: 'copyrit-test1--0000094', Replica: 'copyrit-test1--0000094-6c4d75bc8c-djbqz']
2026-06-08T18:22:13.1916813Z stderr F     return await anext(self.gen)
2026-06-08T18:22:13.1916831Z stderr F            ^^^^^^^^^^^^^^^^^^^^^
2026-06-08T18:22:13.1916850Z stderr F   File "/opt/venv/lib/python3.11/site-packages/fastapi/routing.py", line 216, in merged_lifespan
2026-06-08T18:22:13.1917523Z stderr F     async with original_context(app) as maybe_original_state:
2026-06-08T18:22:13.1917590Z stderr F   File "/usr/lib/python3.11/contextlib.py", line 204, in __aenter__
2026-06-08T18:22:13.1917644Z stderr F     return await anext(self.gen)
2026-06-08T18:22:13.1917666Z stderr F            ^^^^^^^^^^^^^^^^^^^^^
2026-06-08T18:22:13.1917684Z stderr F   File "/app/pyrit/backend/main.py", line 55, in lifespan
2026-06-08T18:22:13.1917702Z stderr F     await config.initialize_pyrit_async()
2026-06-08T18:22:13.1917721Z stderr F   File "/app/pyrit/setup/configuration_loader.py", line 550, in initialize_pyrit_async
2026-06-08T18:22:13.1917741Z stderr F     resolved_initializers = self.resolve_initializers()
2026-06-08T18:22:13.1917759Z stderr F                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^
2026-06-08T18:22:13.1917776Z stderr F   File "/app/pyrit/setup/configuration_loader.py", line 472, in resolve_initializers
2026-06-08T18:22:13.1917800Z stderr F     initializer_class = registry.get_class(config.name)
2026-06-08T18:22:13.1917820Z stderr F                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
2026-06-08T18:22:13.1917840Z stderr F   File "/app/pyrit/registry/class_registries/base_class_registry.py", line 212, in get_class
2026-06-08T18:22:13.1917860Z stderr F     raise KeyError(f"'{name}' not found in registry. Available: {available}")
2026-06-08T18:22:13.1918066Z stderr F KeyError: "'target airt' not found in registry. Available: airt, load_default_datasets, preload_scenario_metadata, scenario_objective_list, scenario_technique, scorer, simple, target"
2026-06-08T18:22:13.1918102Z stderr F 
2026-06-08T18:22:13.1918128Z stderr F ERROR:    Application startup failed. Exiting.

[varunj-msft]

Nice catch on the root cause! Should we apply the same comma fix to parameters.example.json, parameters.demo.json, and the two stale doc mentions in README.md and DEPLOY_NEW_INSTANCE.md? Looks like the manual az deployment path would still hit the same crash otherwise