feat(ui) Chat history import loading component

[gregclark-defenseunicorns]

User Story

As a LFAI user
I want see progress of a chat history import
So that I have direct feedback on the progress of my import

Acceptance Criteria

Given I am importing a chat history
When the import is loading
Then I see the loading component below the search field in the left panel with the text "Chat history import"
If the import is successful
Then I see the complete state of the loading component appear for 1.5 seconds
If the import fails
Then I see the error state of the loading component appear for 1.5 seconds

Additional context

Designs:

• In Progress Import
• Successful Import
• Failed Import