feat: Make workspace watching realtime instead of polling (#4922)

* feat: Make workspace watching realtime instead of polling

This was leading to performance issues on the frontend, where
the page should only be rendered if changes occur. While this
could be changed on the frontend, it was always the intention
to make this socket ~realtime anyways.

* Fix workspace tests waiting, erroring on workspace update, and add comments to workspace events

coderd/database/queries.sql.go

@@ -5487,7 +5487,7 @@ func (q *sqlQuerier) InsertWorkspaceBuild(ctx context.Context, arg InsertWorkspa
 	return i, err
 }
 
-const updateWorkspaceBuildByID = `-- name: UpdateWorkspaceBuildByID :exec
+const updateWorkspaceBuildByID = `-- name: UpdateWorkspaceBuildByID :one
 UPDATE
 	workspace_builds
 SET
@@ -5495,7 +5495,7 @@ SET
 	provisioner_state = $3,
 	deadline = $4
 WHERE
-	id = $1
+	id = $1 RETURNING id, created_at, updated_at, workspace_id, template_version_id, build_number, transition, initiator_id, provisioner_state, job_id, deadline, reason
 `
 
 type UpdateWorkspaceBuildByIDParams struct {
@@ -5505,14 +5505,29 @@ type UpdateWorkspaceBuildByIDParams struct {
 	Deadline         time.Time `db:"deadline" json:"deadline"`
 }
 
-func (q *sqlQuerier) UpdateWorkspaceBuildByID(ctx context.Context, arg UpdateWorkspaceBuildByIDParams) error {
-	_, err := q.db.ExecContext(ctx, updateWorkspaceBuildByID,
+func (q *sqlQuerier) UpdateWorkspaceBuildByID(ctx context.Context, arg UpdateWorkspaceBuildByIDParams) (WorkspaceBuild, error) {
+	row := q.db.QueryRowContext(ctx, updateWorkspaceBuildByID,
 		arg.ID,
 		arg.UpdatedAt,
 		arg.ProvisionerState,
 		arg.Deadline,
 	)
-	return err
+	var i WorkspaceBuild
+	err := row.Scan(
+		&i.ID,
+		&i.CreatedAt,
+		&i.UpdatedAt,
+		&i.WorkspaceID,
+		&i.TemplateVersionID,
+		&i.BuildNumber,
+		&i.Transition,
+		&i.InitiatorID,
+		&i.ProvisionerState,
+		&i.JobID,
+		&i.Deadline,
+		&i.Reason,
+	)
+	return i, err
 }
 
 const getWorkspaceResourceByID = `-- name: GetWorkspaceResourceByID :one