[pallet-xcm] Adjust benchmarks (teleport_assets/reserve_transfer_assets) not relying on ED (#3464)

## Problem
During the bumping of the `polkadot-fellows` repository to
`polkadot-sdk@1.6.0`, I encountered a situation where the benchmarks
`teleport_assets` and `reserve_transfer_assets` in AssetHubKusama
started to fail. This issue arose due to a decreased ED balance for
AssetHubs introduced
[here](https://github.com/polkadot-fellows/runtimes/pull/158/files#diff-80668ff8e793b64f36a9a3ec512df5cbca4ad448c157a5d81abda1b15f35f1daR213),
and also because of a [missing CI
pipeline](https://github.com/polkadot-fellows/runtimes/issues/197) to
check the benchmarks, which went unnoticed.

These benchmarks expect the `caller` to have enough:
1. balance to transfer (BTT)
2. balance for paying delivery (BFPD).
 
So the initial balance was calculated as `ED * 100`, which seems
reasonable:
```
const ED_MULTIPLIER: u32 = 100;
let balance = existential_deposit.saturating_mul(ED_MULTIPLIER.into());`
```
The problem arises when the price for delivery is 100 times higher than
the existential deposit. In other words, when `ED * 100` does not cover
`BTT` + `BFPD`.

I check AHR/AHW/AHK/AHP and this problem has only AssetHubKusama
```
ED: 3333333
calculated price to parent delivery:  1031666634  (from xcm logs from the benchmark)
---

3333333 * 100 - BTT(3333333) - BFPD(1031666634) = −701666667
```
which results in the error;
```
2024-02-23 09:19:42 Unable to charge fee with error Module(ModuleError { index: 31, error: [17, 0, 0, 0], message: Some("FeesNotMet") })
Error: Input("Benchmark pallet_xcm::reserve_transfer_assets failed: FeesNotMet")
     
```

## Solution

The benchmarks `teleport_assets` and `reserve_transfer_assets` were
fixed by removing `ED * 100` and replacing it with `DeliveryHelper`
logic, which calculates the (almost real) price for delivery and sets it
along with the existential deposit as the initial balance for the
account used in the benchmark.


## TODO

- [ ] patch for 1.6 -
https://github.com/paritytech/polkadot-sdk/pull/3466
- [ ] patch for 1.7 -
https://github.com/paritytech/polkadot-sdk/pull/3465
- [ ] patch for 1.8 - TODO: PR

---------

Co-authored-by: Francisco Aguirre <franciscoaguirreperez@gmail.com>

cumulus/pallets/parachain-system/Cargo.toml

@@ -36,6 +36,7 @@ sp-version = { path = "../../../substrate/primitives/version", default-features
 # Polkadot
 polkadot-parachain-primitives = { path = "../../../polkadot/parachain", default-features = false, features = ["wasm-api"] }
 polkadot-runtime-parachains = { path = "../../../polkadot/runtime/parachains", default-features = false }
+polkadot-runtime-common = { path = "../../../polkadot/runtime/common", default-features = false, optional = true }
 xcm = { package = "staging-xcm", path = "../../../polkadot/xcm", default-features = false }
 
 # Cumulus
@@ -79,6 +80,7 @@ std = [
 	"log/std",
 	"pallet-message-queue/std",
 	"polkadot-parachain-primitives/std",
+	"polkadot-runtime-common/std",
 	"polkadot-runtime-parachains/std",
 	"scale-info/std",
 	"sp-core/std",
@@ -102,6 +104,7 @@ runtime-benchmarks = [
 	"frame-system/runtime-benchmarks",
 	"pallet-message-queue/runtime-benchmarks",
 	"polkadot-parachain-primitives/runtime-benchmarks",
+	"polkadot-runtime-common/runtime-benchmarks",
 	"polkadot-runtime-parachains/runtime-benchmarks",
 	"sp-runtime/runtime-benchmarks",
 ]
@@ -110,6 +113,7 @@ try-runtime = [
 	"frame-support/try-runtime",
 	"frame-system/try-runtime",
 	"pallet-message-queue/try-runtime",
+	"polkadot-runtime-common?/try-runtime",
 	"polkadot-runtime-parachains/try-runtime",
 	"sp-runtime/try-runtime",
 ]

cumulus/pallets/parachain-system/src/lib.rs

@@ -1610,6 +1610,15 @@ impl<T: Config> UpwardMessageSender for Pallet<T> {
 	}
 }
 
+#[cfg(feature = "runtime-benchmarks")]
+impl<T: Config> polkadot_runtime_common::xcm_sender::EnsureForParachain for Pallet<T> {
+	fn ensure(para_id: ParaId) {
+		if let ChannelStatus::Closed = Self::get_channel_status(para_id) {
+			Self::open_outbound_hrmp_channel_for_benchmarks_or_tests(para_id)
+		}
+	}
+}
+
 /// Something that can check the inherents of a block.
 #[cfg_attr(
 	feature = "parameterized-consensus-hook",