I used the following CSS to adjust the position, and it works pretty well.
/* Use Flexbox to center chat-channel-unread-indicator__number */
.chat-channel-unread-indicator {
display: flex;
justify-content: center;
align-items: center;
position: relative; /* Ensure the container has a positioning context */
}
/* Ensure the number element's styles do not interfere with centering */
.chat-channel-unread-indicator__number {
display: inline-flex;
align-items: center;
justify-content: center;
}