mathlib3

c562cafa - fix(tactic/itauto): reset after or split (#7387)

fix(tactic/itauto): reset after or split (#7387) Fixes a bug [reported on zulip](https://leanprover.zulipchat.com/#narrow/stream/116395-maths/topic/.60ring.60.20tactic.20for.20types/near/236368947)