Cleanup of unused workflows and bump of Android plugin

[thunderbiscuit]

Preparing for #967.

Bumping the Kotlin Android plugin is just good practice, and is required for the new testing library I use in 967.

The removed workflows are:

• Android API docs. We now build those locally and ship them in the artifact, making them automatically available on javadoc.io
• Live Swift tests. We don't run those anymore and had them on a workflow_dispatch only, but they're just as easily run locally instead. The workflow doesn't add value IMO (let me know if you think it does!)
• Publishing Android. This is an old workflow that doesn't apply anymore with the new plugin and Central Portal. If we ever want to go back to publishing through the CI, it would be using a completely different workflow anyway. Removing the old one for now is cleaner and will make it explicit if we ever create a new one for publication.

[reez]

ACK 3460d98