Take the job you want. Full stop.
You should always do your best to fulfill your obligation to your current employer, and work out a notice they request by policy. In reality, that isn't always possible. Do not lose an opportunity over a formality to a company! If the roles were reversed, the entity would let you go with minimal notice or concern. Managers should understand, we're all humans with ever changing circumstances. Anyone who doesn't has unrealistic expectations.
Good luck in the new job!