[4.0][Cassiopeia] Remove IE11 support from module layout classes

[ciar4n]

Pull Request for Issue #.

Summary of Changes

Removes IE11 support from the module grid layout classes added in #18516

Testing Instructions

Apply this patch and run node build.js --compile-css for updating the changed SCSS. Alternatively, you can run npm i.

Check that #18516 still functions correctly

[brianteeman]

@wilsonge i thought you said we should keep ie11 stuff for the frontend

[N6REJ]

we now have several pr's for the same issue(s) lol
#26242 #26230 #26231

[ciar4n]

That is why we ask for descriptive titles 😉

[wilsonge]

IE11 stuff is fine to remove in this context. We want to make it easy for frontend templates to add support for html5 so I said keep the es5 files bundled with core. So a template doesn’t have to regenerate them all per release for all extensions.

[brianteeman]

Thanks for the clarification