Adding a ToDo does not work when using "Add to Thread" option

[DHaussermann]

When a user creates a ToDo from a post in Mattermost AND checks the option for "Add to thread" a JS error occurs and the save is non functional. I also see a message regarding username. [Util] handleError:: Uncaught TypeError: Cannot read properties of null (reading 'username') Note this happens regardless of weather or not the ToDo is assigned to anyone.

Steps:

• Deploy a build that include the UX overhaul (Can use master)
• Make a post
• Click the action to add a ToDo
• Check the box to add the post to the thread
• Click Save Observed: JS error occurred and save has failed.

[DHaussermann]

@asaadmahmood This seems like it occurs only after the UX changes. Let me know if you're able to take a look.

[AayushChaudhary0001]

@DHaussermann I tried to test and reproduce the above issue but i was not able to do so.

Steps that were followed:-

• Deployed a build from the master branch
• Created a post in channel
• From the action menu, added a todo of the same post.
• Checked the add to thread checkbox and saved.

The ToDo got saved and was reflecting in RHS. cc: @ayusht2810