Custom Actions have unchangeable titles

Bug description

Attempting to change the title while editing a Custom Action just creates a new action instead, after which the old one needs to be manually deleted to remove it.

https://github.com/user-attachments/assets/c88a6b78-04a2-4b0d-9636-7495b7f76ed3

Steps to reproduce

1. Create a Custom Action
2. Edit it
3. Change the title
4. Click save
5. The old Action remains, plus a new one with the new name

Primary pain point(s)

Editing an existing thing should not somehow leave it as-is and create a new thing somewhere else - it's unintuitive and requires extra steps to achieve the most likely intended result.

Additional context

No response

Prerequisites

• I have checked to make sure that a similar request has not already been filed or fixed.

Start by tracing the Custom Action editing and save flow from the UI entry point, then reproduce the title change described in the issue. Done means saving a renamed existing Custom Action updates that action rather than leaving the old action and creating a duplicate; add or run the relevant tests if the project provides them.