[24.0] History import - show user feedback on completion.

[dannon]

Fixes #17933

Just adds a simple info message on history import modal completion (but not cancel) saying that the history has been copied and set to the user's active history:

Also swaps the button back to the standard non-primary-action variant to match more of the 'tertiary action' buttons across the application.

How to test the changes?

(Select all options that apply)

• I've included appropriate automated tests.
• This is a refactoring of components with existing test coverage.
• Instructions for manual testing are as follows:
  1. [add testing steps and prerequisites here if you didn't write automated tests covering all your changes]

License

• I agree to license these and all my past contributions to the core galaxy codebase under the MIT license.

[hexylena]

thanks @dannon this is great!