"Publish Now" button doesn't work for Scheduled posts

[mzorz]

Originally reported by @malinajirka in #9655 (comment)

Expected behavior

Tapping on "Publish Now" for a Scheduled post should show the Publish confirmation dialog and, if the user taps yes, make it published (now).

Actual behavior

A snackbar "Your post is uploading" is shown, but nothing is sent to the server, and no changes are made to the Post.

Steps to reproduce the behavior

1. Blog Posts
2. Schedule a post for next week
3. Notice "Scheduled" label is shown in the post list
4. Open the post and (optionally) make some changes to it (eg. change title)
5. Click on "Publish now" in the overflow menu
6. Notice the publish confirmation dialog is not shown and the post isn't published
7. Go back to post list and notice the post remained untouched (or, alternatively if you modified something in step 4, you'll see "local changes" label on the post).

Tested on [Pixel 2], Android [8.1], WPAndroid [develop]

[mzorz]

Closing via #9661