fix: handle no previous payment updates (#534)

* fix: handle no previous payment updates

* easier to read

x/gmp/types/payment.go

@@ -5,11 +5,13 @@ import (
 	sdk "github.com/cosmos/cosmos-sdk/types"
 )
 
+// TriggerUpdate checks if the payment should be updated based on the current rate and the last update block.
 func (p Payment) TriggerUpdate(rate math.LegacyDec, ctx sdk.Context) bool {
-	// Calculate the percentage difference
+	if p.LastBlock == 0 || p.LastPrice.IsZero() {
+		return true
+	}
 	priceDiff := p.LastPrice.Sub(rate).Abs()
-	percentageDiff := priceDiff.Quo(p.LastPrice).MulInt64(100)
+	deviationExceeded := priceDiff.Quo(p.LastPrice).MulInt64(100).GT(p.Deviation)
 
-	return percentageDiff.GT(p.Deviation) ||
-		p.LastBlock < ctx.BlockHeight()-p.Heartbeat
+	return deviationExceeded || p.LastBlock < ctx.BlockHeight()-p.Heartbeat
 }