Nope, no auto attacks in eso.

If you're really that worried about your mouse health (I've never worn a mouse out in years of playing PC games, so can't speak to how common a problem this is), another option would be to bind light attack to a keyboard button and then run a heavy attack build. Then you just hold a key button down instead of light attacks. I think you're allowed to bind it that way? You can certainly deal a lot of damage with the right build this way, so that part's not a problem.

There's also a Mythic item you can farm with Antiquities called Velothi Ur-Mage Amulet that drastically reduces your light attack damage in exchange for PvE buffs. (You still want to generate ultimate by hitting a light attack or healing someone every 3 seconds)

Or spam fatecarver.

Have fun!