Used align hook in columns block; Fixed columns alignment bug;

[jorgefilipecosta]

This PR makes column class make use of the align hook, by using supports: align. This change fixes a bug where align classes were not passed to the frontend.

Fixes: #5117

How has this been tested?

Verify the columns block continue to work as expected, verify it is possible to align it to 'wide' or 'full' and then the corresponding class is passed to the frontend.

[gziolo]

I wanted to introduce a similar change in #5099. If you look at https://github.com/WordPress/gutenberg/pull/5099/files#diff-89d3b001ccbb88ada880aa2d5db1c55bR58, getEditWrapperProps was also removed because it is handled by hooks.

[gziolo]

I did the same in #5099, we use align with Paragraph block. However, we didn't roll this out to all blocks because we didn't find a solid way to tackle server-side rendered blocks. The issue is that those hooks that modify blocks to add support for align are executed only on the client. There needs to be a way to have the same behavior on the server to make sure that align attributes is listed when rendering dynamic block.

On the technical level, this PR is good to go after no longer needed getEditWrapperProps is removed. The question remains if we should do it or wait as @aduth suggested until this solution is bullet-proof.

[jorgefilipecosta]

Hi @gziolo, I'm sorry I did not remember that your PR also did this change. Given that your PR is on hold until we solve the server side blocks challenge, I think it would be ok to merge this one as it solves a bug. We are already using supports: align in some blocks like audio so it would basically be one more block using it :)
getEditWrapperProps was removed.

[gziolo]

It's good to go as I mentioned earlier.