Make standard `SWAP` note "in-flight" fillable

### Feature description

## Background:

Currently for an `Account` to consume the standard `SWAP` note, the `Account` must have the `REQUESTED_ASSET` amount in the account's asset vault.

This is suboptimal from a liquidity point of view, since it is possible for `SWAP` notes to use their liquidity to fill each other.

Say there are two "complimentary" `SWAP` notes:
* `SWAP` note 1: 10 token A for 5 token B
* `SWAP` note 2: 2.5 token B for 5 token A

These two `SWAP` notes can be filled against each other using the liquidity of the other `SWAP` note. These two `SWAP` notes agree on the same price. If they did not agree on the price, the would not be complementary. Additionally, it is also possible for the sell price of one `SWAP` note to be lower than the buy price of another `SWAP` note. This would result in a potential arbitrage opportunity for the solver matching these two `SWAP` notes.

With the current `SWAP` note, the `Account` which consumes these two `SWAP` notes must have 5 tokens B and 5 tokens A, when their net asset delta will be 0 if they fill these two notes against each other.

Filling `SWAP` notes 1 & 2 against each other would produce the following notes:
```mermaid
flowchart LR
I1[SWAP1
offer 10A / want 5B] --> TX((Maker Account))
I2[SWAP2
offer 2.5B / want 5A] --> TX

TX --> O3[SWAP1'
offer 5A / want 2.5B]
TX --> O1[P2ID: 2.5B -> SWAP1 owner]
TX --> O2[P2ID: 5A -> SWAP2 owner]

```

It is not necessary for the `Maker Account` to have any assets at all in their asset vault to fill these two `SWAP` notes against each other. The ability to fill `SWAP` notes against each other, is what I refer to as "in-flight" `SWAP` note filling.

________

## Proposal:

Make it possible for `SWAP` notes to be filled "in-flight` against each other. [I opened a PR](https://github.com/0xMiden/protocol/pull/1904) a while back which implemented this.

Since we are moving closer to audits, I propose we add this feature to the standard SWAP note. This adds an `if / else` branch to the `SWAP` note which checks if the consuming `Account` has sufficient liquidity in its asset vault to fill the `SWAP` note. If not, the `SWAP` note assumes it is being filled in the context of a batch of `SWAP` notes.

#1904 will need to be refactored to be updated to the latest state of `next`

### Why is this feature needed?

The current `SWAP` note implementation is not flexible for solvers.