Add edit history item

[rebeccaalpert]

Add a way to edit history items in chat history.

See design: patternfly/patternfly-design-kit#797

The meat of this is to go into ChatbotConversationHistoryNav and change the logic where the <MenuItem> gets generated to optionally add an input that can be triggered based on some conversation prop.

Needs example for docs and tests, as well as any additional code to get this working. We don't want to hard-code the dropdown item for edit, but we should add an example where it exists.

[kaylachumley]

related issue: patternfly/patternfly-design-kit#797

[kaylachumley]

the designs are ready to go for you to start implementing! notes in my design issue