Quick fix for update client when trusted_height == target_height

[soareschen]

Closes: #997

Description

Quick fix of #997 that is extracted from the proper fix #1011.

---

For contributor use:

• Updated the Unreleased section of CHANGELOG.md with the issue.
• If applicable: Unit tests written, added test to CI.
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
• Updated relevant documentation (docs/) and code comments.
• Re-reviewed Files changed in the Github PR explorer.

[romac]

Do we still need this assertion here? I guess we still expect the events vec to be non-empty but since we can now gracefully handle the case where it's not, perhaps we could convert it to a debug_assert!?

[soareschen]

I think it is fine to remove it. I checked the callers and none of them are really doing anything with the result returned. Otherwise it would depends on whether the other functions check on the events returned. If we want to do checking, it should still return an Err result instead of using assert! or debug_assert!.

[ancazamfir]

Let's discuss this, see #997 (comment)

[adizere]

#997 is easy to handle and will be fixed in another PR.