Revert CoreImageAttributes width field is of type String but it should be Float

[ChrisWiegman]

Steps to Reproduce

Check CoreImageAttributes width type in GraphQLi. It is of type String.

##Issue
CoreImageAttributes.width is of type String.

##Expected Behavior
CoreImageAttributes.width should be of type Float.

##Additional Information
Note any other relevant details.

##Related ticket:
CoreImageAttributes.width is type String, but should be a Float · Issue #136 · wpengine/wp-graphql-content-blocks
You need to revert the following commit: Bug: CoreImage width attribute resolve throws error. (#130) · wpengine/wp-graphql-content-blocks@28fca4a
However we need to document the failing unit test case and provide a workaround for this error.
The workaround is to use an alias for the attributes field so that GrapgQL can resolve the types without any conflicts.

[justlevine]

I believe i noted this in #136, but just in case: the ideal fix from a schema perspective is to make all width/height attributes a CssUnit { value: Int, unit:CssUnitTypeEnum } or similar, where the unit type defaults if there isn't an explicit one.

[ChrisWiegman]

@justlevine I'm sure you did. We're in the process of converting from Jira to GitHub for the teams own work and, as much as I tried to catch all the dupes in moving over work, I'm sure there are a few.