conversation: Split out message parsing
Current code would not check if messages are empty
log_data->msg = g_strdup (line_split[1]);
While fixing that I noticed that GStrv's are being leaked so fix this too by moving this into a easier to validate function. This
- uses a new GStrv for every split
- g_strdups the string right before assigning it to ChattyLog
- g_auto frees the variables