remove superfluous signature optimization

When replaying parts that were waiting for an on-the-fly funding, we
explicitly set `commit = false` to all parts but the last one, in order
to save us from signing multiple times.

But this has side effects in the case where the last part is rejected
for some reason, because previous parts stay stuck waiting for a
`CMD_SIGN` that never arrives.

Author: pm47

eclair-core/src/main/scala/fr/acinq/eclair/payment/relay/OnTheFlyFunding.scala

@@ -292,9 +292,7 @@ object OnTheFlyFunding {
           // This lets us detect that this HTLC is an on-the-fly funded HTLC.
           val htlcFees = LiquidityAds.FundingFee(remainingFees.min(p.maxFees(htlcMinimum)), cmd.status.txId)
           val origin = Origin.Hot(htlcSettledAdapter.toClassic, p.upstream)
-          // We only sign at the end of the whole batch.
-          val commit = p.htlc.id == cmd.proposed.last.htlc.id
-          val add = CMD_ADD_HTLC(cmdAdapter.toClassic, p.htlc.amount - htlcFees.amount, paymentHash, p.htlc.expiry, p.htlc.finalPacket, p.htlc.blinding_opt, 1.0, Some(htlcFees), origin, commit)
+          val add = CMD_ADD_HTLC(cmdAdapter.toClassic, p.htlc.amount - htlcFees.amount, paymentHash, p.htlc.expiry, p.htlc.finalPacket, p.htlc.blinding_opt, 1.0, Some(htlcFees), origin, commit = true)
           cmd.channel ! add
           remainingFees - htlcFees.amount
       }

eclair-core/src/test/scala/fr/acinq/eclair/payment/relay/OnTheFlyFundingSpec.scala

@@ -867,8 +867,7 @@ class OnTheFlyFundingSpec extends TestKitBaseClass with FixtureAnyFunSuiteLike {
       assert(add.fundingFee_opt.nonEmpty)
       assert(add.fundingFee_opt.get.fundingTxId == purchase.txId)
     })
-    adds1.take(1).foreach(add => assert(!add.commit))
-    assert(adds1.last.commit)
+    adds1.foreach(add => assert(add.commit))
     assert(adds1.map(_.fundingFee_opt.get.amount).sum == fees.total.toMilliSatoshi)
     assert(adds1.map(add => add.amount + add.fundingFee_opt.get.amount).sum == 110_000_000.msat)
     channel.expectNoMessage(100 millis)