Fix poetry not found issue in mise in Duo Workflow service

Fix poetry not found issue in mise when setting up Duo Workflow service.

Running cd in non-interactive mode doesn't call the required mise shell hooks. This results in poetry command which is managed by mise to fail.

$ make duo-workflow-service/poetry-install

--------------------------------------------------------------------------------
Installing mise tools from /Users/tanle/code/gitlab/gdk/duo-workflow-service/.tool-versions
--------------------------------------------------------------------------------
cd /Users/tanle/code/gitlab/gdk/duo-workflow-service && mise install -y
mise all runtimes are installed

--------------------------------------------------------------------------------
Building duo-workflow-service/poetry-install version main
--------------------------------------------------------------------------------
support/asdf-exec duo-workflow-service poetry install
support/asdf-exec: line 23: poetry: command not found
make: *** [support/makefiles/Makefile.duo-workflow-service.mk:68: duo-workflow-service/poetry-install] Error 127

How to set up and validate locally

1. Ensure GitLab Duo Workflow service is enabled by adding the below configuration in gdk.yml:

   ---
   duo_workflow:
     enabled: true
   mise:
     enabled: true

2. Check out to this merge request's branch.
3. Run gdk reconfigure to check if regenerating all configuration is successful.
4. Run the following command to update gitlab-ai-gateway and confirm the error no longer shows.

   $ make duo-workflow-service/poetry-install                                                      
                                                                                                   
   --------------------------------------------------------------------------------                
   Installing mise tools from /Users/tanle/code/gitlab/gdk/duo-workflow-service/.tool-versions                                                                                                     
   --------------------------------------------------------------------------------                
   cd /Users/tanle/code/gitlab/gdk/duo-workflow-service && mise install -y                         
   mise all runtimes are installed                                                                                                                                                                 
                                                                                                   
   --------------------------------------------------------------------------------                
   Building duo-workflow-service/poetry-install version main                                                                                                                                       
   --------------------------------------------------------------------------------                
   support/asdf-exec duo-workflow-service mise exec -- poetry install                              
   Creating virtualenv duo-workflow-service in /Users/tanle/code/gitlab/gdk/duo-workflow-service/.venv                                                                                             
   Installing dependencies from lock file                                                          
                                                                                                   
   Package operations: 103 installs, 1 update, 0 removals                 
   --snip--

Impacted categories

The following categories relate to this merge request:

• gdk-reliability - e.g. When a GDK action fails to complete.
• gdk-usability - e.g. Improvements or suggestions around how the GDK functions.
• gdk-performance - e.g. When a GDK action is slow or times out.

Merge request checklist

• This change is backward compatible. If not, please include steps to communicate to our users.
• Tests added for new functionality. If not, please raise an issue to follow-up.
• Documentation added/updated, if needed.
• Announcement added, if change is notable.
• gdk doctor test added, if needed.
• Add the ~highlight label if this MR should be included in the CHANGELOG.md.