The transaction system contains a necessary optimization where a popped
transaction is combined with later, similar transactions. This breaks
the chronological order of states, and can lead to desynchronized
geometries.
To fix this, we replace the queue with only 2 transactions: current and
pending. If a pending transaction exists, it is updated with new state
instead of creating additional transactions.
As we never have more than a single waiting transaction, we no longer
need the queue optimization that is causing problems.
Closes: https://github.com/swaywm/sway/issues/6012
c8bf84c82d