fix else block transition update

[tanhauhau]

Fixes #5573

If the outro transition gets aborted before finished, the outro callback is not called, therefore the if_blocks[1] is not cleared yet.
In this case, we need to update the block with the latest state

Before submitting the PR, please make sure you do the following

• It's really useful if your PR references an issue where it is discussed ahead of time. In many cases, features are absent for a reason. For large changes, please create an RFC: https://github.com/sveltejs/rfcs
• This message body should clearly illustrate what problems it solves.
• Ideally, include a test that fails without this PR but passes with it.

Tests

• Run the tests with npm test and lint the project with npm run lint