feat: Add Snap UI avatar component

[FrederikBolding]

Description

Move Snaps UI avatar implementation to a separate component that can be consumed by Snaps.

Related issues

Closes: MetaMask/snaps#2776

Manual testing steps

export const onRpcRequest: OnRpcRequestHandler = async ({
  origin,
  request,
}) => {
  switch (request.method) {
    case 'hello':
      return snap.request({
        method: 'snap_dialog',
        params: {
          type: 'confirmation',
          content: (
            <Box>
              <Text>
                Hello, <Bold>{origin}</Bold>!
              </Text>
              <Text>
                This custom confirmation is just for display purposes.
              </Text>
              <Text>
                But you can edit the snap source code to make it do something,
                if you want to!
              </Text>
              <Address address='eip155:1:0x1234567890123456789012345678901234567890' />
              <Avatar address="eip155:1:0x1234567890123456789012345678901234567890" />
              <Address address="bip122:000000000019d6689c085ae165831e93:128Lkh3S7CkDTBZ8W7BbpsN3YYizJMp8p6" />
              <Avatar address="bip122:000000000019d6689c085ae165831e93:128Lkh3S7CkDTBZ8W7BbpsN3YYizJMp8p6" />
              <Box direction="horizontal" alignment="space-between" center={true}>
                <Text>Avatar</Text>
                <Avatar address="bip122:000000000019d6689c085ae165831e93:128Lkh3S7CkDTBZ8W7BbpsN3YYizJMp8p6" />
              </Box>
 
            </Box>
          ),
        },
      });
    default:
      throw new Error('Method not found.');
  }
};

Screenshots/Recordings