fix(revenuecat): clear duration default when endTimeMs is provided

The duration dropdown defaults to 'monthly' so any user filling in the
advanced endTimeMs field would otherwise hit the XOR guard. Clear
duration in the params mapper so endTimeMs takes precedence.

apps/sim/blocks/blocks/revenuecat.ts

@@ -399,6 +399,7 @@ Return ONLY the numeric timestamp, no text.`,
         }
         if (params.endTimeMs !== undefined && params.endTimeMs !== '') {
           next.endTimeMs = Number(params.endTimeMs)
+          next.duration = undefined
         }
         if (params.expiryTimeMs !== undefined && params.expiryTimeMs !== '') {
           next.expiryTimeMs = Number(params.expiryTimeMs)