Improve load time perception when generating summary

Issue

When clicking on the "View summary" button, I can take a couple of seconds to create the summary depending on the amount of activity is available.

Current loading experience
Load_time-_2023-06-08_at_10.41.08_AM

Proposals

Option A (low effort)

Once the button is clicked, show the content container
Show a skeleton loader in the content container

Option B (semi low effort)

Same as Option A, plus:
"Say what the AI is doing"
Animate text in the content container, similar to https://gitlab.com/gitlab-org/gitlab/-/issues/413213#proposed-solution

Option C (More effort)

Pull up people's avatars from the discussions and animate them somehow. Either so it looks like they are having a conversation, or just spin or bounce them around.

Source: &10344 (comment 1417716409)

Conclusion

In order to move things forward, I recommend we move forward with Option A.