Gutenberg: Remove 'type' from attributes where 'source' is set.

[miina]

Removes 'type' from attributes where 'source' is set, apparently that was deprecated in 4.1.0, removed in 4.2.0 and is now causes issues with blocks and extended features.

Note that type isn't mandatory for other cases either (if the source is not set at all).

[miina]

@kienstra and @westonruter:
This PR should fix most of the custom blocks and some custom AMP features not working in Gutenberg.

For some reason the branch 1.0 is showing some additional file changes as well, would it be better if I'd create the PR into develop?

There is another branch doing the same thing but based on develop if that's better:
https://github.com/Automattic/amp-wp/compare/fix/block-attributes?expand=1

[westonruter]

For some reason the branch 1.0 is showing some additional file changes as well, would it be better if I'd create the PR into develop?

Fixed by cherry-picking your commit onto 1.0 and then force-pushing to this branch.

[kienstra]

Approved

Hi @miina,
Thanks for fixing this. All of the blocks that this affects looks good, except for some issues not related to this PR (mentioned below).

amp-fit-text

amp-brid-player

amp-ima-video

amp-jwplayer

Issues Unrelated To PR

The <amp-springboard-player> doesn't render, but it doesn't render on ampbyexample.com, either. This could be a matter of finding the right attribute values to test this.

There's a validation error for the <amp-o2-player>, though I don't think it's related to this PR. I'll open a separate issue for this:

[kienstra]

amp-o2-player

This wasn't related to this PR. But the problem I mentioned above with the <amp-o2-player> doesn't seem to exist when using the attribute values from ampbyexample.com: