Palantir's recent pullback does little to offset a valuation that already assumes years of flawless execution in a brutally competitive AI software market.Palantir Technologies (PLTR 0.57%) has given investors a fresh reminder that momentum cuts both ways. After a stunning run earlier this year, the software company behind data-integration and AI (artificial intelligence) platforms for governments and enterprises has seen its share price slide more than 15% from levels earlier this month.That kind of pullba ...