Because pipeline status could be changed for the builds in the next
stages, if we process next stages first, the current build would be
out of synchronized, and would need a reload for that matter.

Alternatively, like what I did in this commit, we could process the
next stages later (by using `after_transition` rather than
`around_transition`), and complete what're doing for the current
build first. This way we don't have to reload because nothing is
out synchronized.

Note that since giving `false` in `after_transition` would halt the
callbacks chain, according to:

https://github.com/state-machines/state_machines-activemodel/blob/v0.4.0/lib/state_machines/integrations/active_model.rb#L426-L429

We'll need to make sure we're not returning false because we don't
intend to interrupt the chain.

This fixes #22010.

After this fix, both pipeline events and build events would only show
up once.