Currently it's only possible to request Planner endpoints with a delegated token. App only tokens are not supported.
Instead of getting a Graph error, we could display an error message like This command is not supported with application permissions.

We cannot check the token in the validation stage. This check should be done first in the commandAction method.

Commands to update:

• planner plan add
• planner plan get
• planner plan details get
• planner plan list
• planner task add
• planner task get
• planner task list
• planner task set
• planner task details get
• planner bucket add
• planner bucket get
• planner bucket list
• planner bucket set
• planner bucket remove (when Adds planner bucket remove command. Closes #2742 #3250 is completed)

Discussed in #3261