Fix commit-time cleanup of chains of empty relations

Usage and product changes

In cases where chains of empty relations existed, for example r1 -> r2 -> r3... -> rX, it was possible that TypeDB did not correctly execute the automatic relation cleanup due to the order the relations happened to be traversed.

TypeDB now retries the commit-time cleanup of empty relations until there are no new deletions. We accept the higher runtime cost of this operation since 1) we expect the number of modified relations in a transaction to be relatively small (no more than thousands) 2) relation chains are relatively rare 3) relation chains that must clean up in dependent fashion are extremely rare.

Implementation

Add a loop that retries relation cleanup until no more relations are deleted.

PR Review Checklist

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Trivial Change

[x] This change is trivial and does not require a code or architecture review.

Code

[ ] Packages, classes, and methods have a single domain of responsibility.
[ ] Packages, classes, and methods are grouped into cohesive and consistent domain model.
[ ] The code is canonical and the minimum required to achieve the goal.
[ ] Modules, libraries, and APIs are easy to use, robust (foolproof and not errorprone), and tested.
[ ] Logic and naming has clear narrative that communicates the accurate intent and responsibility of each module (e.g. method, class, etc.).
[ ] The code is algorithmically efficient and scalable for the whole application.

Architecture

[ ] Any required refactoring is completed, and the architecture does not introduce technical debt incidentally.
[ ] Any required build and release automations are updated and/or implemented.
[ ] Any new components follows a consistent style with respect to the pre-existing codebase.
[ ] The architecture intuitively reflects the application domain, and is easy to understand.
[ ] The architecture has a well-defined hierarchy of encapsulated components.
[ ] The architecture is extensible and scalable.

vaticle / typedb