az containerapp up fails with: TypeError: argument of type 'NoneType' is not iterable

### Describe the bug

Az containerapp up command is failing with TypeError: argument of type 'NoneType' is not iterable

### Related command

/usr/local/bin/az containerapp up -n genevabuddytest-fpa -g grafanaEmbedding -i .azurecr.io/genevabuddytest:1.2.0-buddy.108 --registry-server .azurecr.io --registry-username --registry-password *** --env-vars GFAZPL_USER_IDENTITY_ENABLED=true GFAZPL_USER_IDENTITY_CLIENT_ID=*** GFAZPL_USER_IDENTITY_CLIENT_SECRET=*** GFAZPL_USER_IDENTITY_TOKEN_URL=https://authproxytest.blackisland-51b08931.westus3.azurecontainerapps.io/oauth2/v2.0/token GFAZPL_USER_IDENTITY_ASSERTION=username --ingress external --target-port 3000

### Errors

WARNING: Using resource group 'grafanaEmbedding'
WARNING: Using ContainerAppEnvironment 'authproxytest-env' in resource group grafanaEmbedding
WARNING: Updating Containerapp genevabuddytest-fpa in resource group grafanaEmbedding
ERROR: The command failed with an unexpected error. Here is the traceback:
ERROR: argument of type 'NoneType' is not iterable
Traceback (most recent call last):
File "/usr/local/lib/python3.8/site-packages/knack/cli.py", line 233, in invoke
cmd_result = self.invocation.execute(args)
File "/usr/local/lib/python3.8/site-packages/azure/cli/core/commands/__init__.py", line 663, in execute
raise ex
File "/usr/local/lib/python3.8/site-packages/azure/cli/core/commands/__init__.py", line 726, in _run_jobs_serially
results.append(self._run_job(expanded_arg, cmd_copy))
File "/usr/local/lib/python3.8/site-packages/azure/cli/core/commands/__init__.py", line 718, in _run_job
return cmd_copy.exception_handler(ex)
File "/usr/local/lib/python3.8/site-packages/azure/cli/command_modules/containerapp/_client_factory.py", line 28, in _polish_bad_errors
raise ex
File "/usr/local/lib/python3.8/site-packages/azure/cli/core/commands/__init__.py", line 697, in _run_job
result = cmd_copy(params)
File "/usr/local/lib/python3.8/site-packages/azure/cli/core/commands/__init__.py", line 333, in __call__
return self.handler(*args, **kwargs)
File "/usr/local/lib/python3.8/site-packages/azure/cli/core/commands/command_operation.py", line 121, in handler
return op(**command_args)
File "/usr/local/lib/python3.8/site-packages/azure/cli/command_modules/containerapp/custom.py", line 3612, in containerapp_up
##[error]Error Code: [1]
##[error]Error: Unable to update Azure Container App via 'az containerapp update' command.
app.create(no_registry=bool(repo))
File "/usr/local/lib/python3.8/site-packages/azure/cli/command_modules/containerapp/_up_utils.py", line 392, in create
return containerapp_up_logic(
File "/usr/local/lib/python3.8/site-packages/azure/cli/command_modules/containerapp/custom.py", line 3632, in containerapp_up_logic
return update_containerapp_logic(cmd=cmd, name=name, resource_group_name=resource_group_name, image=image, replace_env_vars=env_vars, ingress=ingress, target_port=target_port,
File "/usr/local/lib/python3.8/site-packages/azure/cli/command_modules/containerapp/custom.py", line 387, in update_containerapp_logic
if "properties" in containerapp_def and "template" in containerapp_def["properties"] and "containers" in containerapp_def["properties"]["template"]:
TypeError: argument of type 'NoneType' is not iterable

### Issue script & Debug output

I can attach if needed

### Expected behavior

Able to deploy containerapp

### Environment Summary

{
"azure-cli": "2.56.0",
"azure-cli-core": "2.56.0",
"azure-cli-telemetry": "1.1.0",
"extensions": {
"amg": "1.2.9"
}
}

### Additional context

_No response_