Alerting: Set error annotation on EvaluationError regardless of underlying error type

[alexweav]

What is this feature?

Previously we only set the error annotation on a state if the expr.Result's attached error is an expr.QueryError. This assumes that the expression engine always wraps its error types consistently. If it fails to do so, there is no Error annotation.

This PR makes it so we always set the Error annotation for all errors, regardless of its type. This appears to be a bug based on the comment, which intends to just add special fields from expr.QueryError like ref_id/datasource_uid

Which issue(s) does this PR fix?:

n/a

Special notes for your reviewer:

[grafanabot]

The backport to v9.3.x failed:

The process '/usr/bin/git' failed with exit code 1

To backport manually, run these commands in your terminal:

# Fetch latest updates from GitHub
git fetch
# Create a new branch
git switch --create backport-61506-to-v9.3.x origin/v9.3.x
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x b289b8ac6e84816ebdcd00b6d76b8cd60a7bc8e8
# Push it to GitHub
git push --set-upstream origin backport-61506-to-v9.3.x
git switch main
# Remove the local backport branch
git branch -D backport-61506-to-v9.3.x

Then, create a pull request where the base branch is v9.3.x and the compare/head branch is backport-61506-to-v9.3.x.