fix: deletion of invocation impacting whole invocation secondary index

[seriousben]

Context

As part of supporting the pagination of list invocations, a bug was introduced that would hide invocations of the compute graph from the list invocations if one invocation is deleted.

What

This PR addresses the issue by:

• Deleting a single entry in the invocation secondary index as opposed to a prefix scan.
• Adding a migration (and revamping migrations) in order to recreating the invocation secondary index which will make visible all the invocations that became hidden.
• Improving how list invocations is being paginated in order to address UI and API issues.

Testing

Contribution Checklist

• If a Python package was changed, please run make fmt in the package directory.
• If the server was changed, please run make fmt in server/.
• Make sure all PR Checks are passing.