Fix issues with drafting release notes in CI (#10955)

This PR addresses some issues I ran into with the way we draft release
notes in CI when doing builds.

The first issue I encountered was that `script/draft-release-notes` was
failing, seemingly due to CI doing a shallow Git checkout and not having
all of the tags available in order to compare then. This was addressed
by setting the `fetch-depth` during the Git checkout.

The second issue is that (in my opinion) we shouldn't fail the build if
drafting release notes fails. After well, we're doing it as a
convenience to ourselves, and it isn't a mandatory part of the build.
This was addressed by making any failures in
`script/draft-release-notes` not fail the CI step as a whole.

These changes were already applied to the `v0.133.x` branch.

Release Notes:

- N/A