Chat: renderTextWithLinks now properly handles |cAARRGGBB color codes
that aren't item links (e.g. colored player names), rendering the text
in the specified color instead of discarding it.
Dismount: Classic/Vanilla lacks CMSG_CANCEL_MOUNT_AURA (TBC+ opcode).
Track mount aura spell ID when mountDisplayId changes, then use
CMSG_CANCEL_AURA as fallback on expansions without the dedicated opcode.