account for possible step application failure during rebase

[jgravois]

hi @marijnh 👋

we intermittently see steps which can be applied cleanly locally, but induce an error when rebased on top of remote confirmed steps.

i am aware that maybeStep() possibly throwing is by design. locally i'm seeing desirable behavior with the patch here, which simply ignores the failed steps altogether.

things i'm unsure of:

1. does more need to be done to purge these failed steps from any other unconfirmed steps that may be present?
2. is there something i could be doing outside of the collab plugin to make these steps more invertable/rebasable?

i haven't been able to isolate a simplified repro case for this error yet but i'm happy to describe the scenario in more detail if it would be helpful. the short version is (unsurprisingly), 'its complicated' 🙃

fwiw, with the same code, we're seeing this error orders of magnitude more frequently in prosemirror-transform@1.8.0 than prosemirror-transform@1.4.2

[marijnh]

we intermittently see steps which can be applied cleanly locally, but induce an error when rebased on top of remote confirmed steps.

This suggests there is a problem in the way you are collecting or rebasing these steps. This patch is definitely not the solution. Code that silently swallows errors here is not something I'm going to merge.