Is the titration of sodium carbonate with hydrochloric acid temperature dependent?
I think you might have a different understanding of what constitutes a 'change in the observation/reading' from the textbook, resulting in your confusion.

I am assuming that the textbook is only considering the titration graph per se, pH vs volume of acid added.

You are referring to the time to pH equilibrium during each drop of acid added. For the purposes of all titrations I have encountered, this was never a factor that was discussed. As @Ivan Neretin commented, the reaction is assumed to occur instantly.

As the concentration of the species remains the same, the titration graph will look the same. In other words: The temperature has no influence on the equivalence point.