[REFACTOR] update `UnsupportedContent` rendering

[musale]

Describe the bug
Currently, rendering the UnsupportedContent component is done by stringifying the component and appending it as a string in the content property. This brings in state mutation of the props that is not advised.

To Reproduce
Steps to reproduce the behavior:

1. Go to

   microsoft-graph-toolkit/packages/mgt-chat/src/utils/chat.tsx

   Lines 15 to 24 in 2a61bd7

   	const onRenderMessage = (messageProps: MessageProps, defaultOnRender?: MessageRenderer) => {
   	const message = messageProps?.message;
   	if (isGraphChatMessage(message) && message?.hasUnsupportedContent) {
   	const unsupportedContentComponent = <UnsupportedContent targetUrl={message.rawChatUrl} />;
   	messageProps = produce(messageProps, (draft: MessageProps) => {
   	if (isChatMessage(draft.message)) {
   	draft.message.content = renderToString(unsupportedContentComponent);
   	}
   	});
   	}

Expected behavior
Rendered UnsupportedContent component as a react component. Wrap it in ChatMessage or ChatMyMessage components from @fluentui/react-components. Add the chat message header customizations for a similar look to the rest of the messages. Remove any state mutations on the props passed in onRenderMessage.

Additional Context

• 062cc3c for adding ChatMessage and ChatMyMessage
• 0789365 for customizing the chat message header
• First consider merging in feat: render adaptive cards #2746

[gavinbarron]

Good call @musale

[sebastienlevert]

In a case where we want developers to provide their own logic to render the content (replace an adaptive card, for instance), we should provide a onUnsupportedContentRender callback that developers can use to return a JSX element if required.

[musale]

In a case where we want developers to provide their own logic to render the content (replace an adaptive card, for instance), we should provide a onUnsupportedContentRender callback that developers can use to return a JSX element if required.

Good idea, we should make this its own issue. Update: #3122