Replace object type defs with dictionary type

[waltjones]

Description of the change

In many places, the type definitions for callback functions use the object type for payload or item arguments. This makes the object opaque and no properties can be accessed in the callback.

This PR updates these to use a generic dictionary type.

Type of change

• Bug fix (non-breaking change that fixes an issue)

Related issues

Fixes
https://app.shortcut.com/rollbar/story/120642/
#985

Development

• Lint rules pass locally
• The code changed/added as part of this pull request has been covered with tests
• All tests related to the changed code pass in development

Code review

• This pull request has a descriptive title and information useful to a reviewer. There may be a screenshot or screencast attached
• Issue from task tracker has a link to this pull request
• Changes have been reviewed by at least one other engineer

[mudetroit]

I sent you an sidechannel note on something here. That said this code is as safe as what it replaces.