Add initial and colorful avatars

[thatblindgeye]

Chatbot Component Area

Message Content (Text, Markdown, Citations)

Describe the feature

Once patternfly/patternfly#8116 and a React followup are merged in, we need to pull the feature into chatbot and allow consumers to implement it

Expected Data Structure

No response

Conversational Flow

No response

Visuals & Mockups

No response

Conversational Accessibility

No response

Validation

• This request aligns with PatternFly AI/Chatbot design guidelines.

• I have searched for existing chatbot-specific components.

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Jira Issue: PF-4199