test: run e2e tests on pre-compiled packages

[jbedard]

The NPM packages to test must be specified via --package instead of invoking the build from within the e2e tests

This means the packages must be built before tested. This will align with bazel which will pass the bazel built (and cached) tgz files. The packages being tested could be the real npm packages before being published, although CI will probably test snapshot-like packages.

[alan-agius4]

NIT: in general it would be great that the PR description is part of the commit message. As it add more context when checking the commit history.

[jbedard]

I've updated the commit message a bit (and rebased). Let me know if there's other information you think should be in there.

[jbedard]

~~FWIW CODE_OF_CONDUCT.md is currently causing the CI "validation" step to fail.~~

[jbedard]

Updated and squashed, see diff

[angular-automatic-lock-bot[bot]]

This issue has been automatically locked due to inactivity. Please file a new issue if you are encountering a similar or related problem.

Read more about our automatic conversation locking policy.

_{This action has been performed automatically by a bot.}