Do not upload HTML if non-HTML output fails

[humitos]

It seems that we are uploading the HTML output immediately after it completes. However, it may happen that the build fails after that because the PDF output fails or for any other reason.

We should double-check what's the status of this and upload all the outputs at once after we are sure the build passed.

---

@humitos Because HTML was being uploaded directly after it was built to increase the speed of publishing. I thought we'd reverted this, but if we haven't we should. I agree it shouldn't publish if the build doesn't pass.

There is also the issue of the PDF builds failing even while producing valid output, but that's a different issue.

Originally posted by @ericholscher in #8612 (comment)

[humitos]

We could double-check this in code because I think we have changed the pattern here and we always upload everything after the build was built successfully.

[humitos]

Yes, we upload all the artifacts after the build process has finished:

readthedocs.org/readthedocs/projects/tasks/builds.py

Line 831 in 3eae8f5

self.store_build_artifacts()