[pulsarbot] Add option to re-run all tests (even if they succeeded)

## Purpose
When testing for flaky tests, it is often useful to be able to trigger all tests to be re-run.

## Context
In the past, when I wanted to get all the tests to run again, I would make an arbitrary change to a comment in one of the code files to trigger a new build. However, this has not been working recently. (Instead, the builds all just automatically pass instead of completely running again.)

## New Feature
Currently, `pulsarbot` is capable of triggering failed tests to be re-run, but it doesn't currently support an option to re-run tests that passed.
Please add this support to the `pulsarbot` that listens to comments in the PRs to trigger build actions.

@sijie This one is for you. :)

Start by locating the TypeScript pulsarbot code that listens to pull-request comments and the existing path for re-running failed tests. Determine how a new option should request all tests, then verify that both previously failed and previously successful tests run again through the build actions.

Written by the indexing model from the issue text.