Update bot avatar icon

[kaylachumley]

Update the bot icon used in the avatar to match the new robot icon that was created as apart of the AI enablement team work. The robot icon will be the recommended standard for representing AI or "bot" responses.

We will need to show this icon in light and dark them switching to be inverse colors. The Robot icon is apart of the Redhat brand library. Connect with @kaylachumley for questions

example:

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Jira Issue: PF-3650

[kaylachumley]

related design issue: https://issues.redhat.com/browse/PF-3653

[thatblindgeye]

We likely will want to inverse the icon colors in dark mode to be wwhite on a black/grey background.