feat(daffio): clean up why pwa page styles

[xelaint]

PR Checklist

Please check if your PR fulfills the following requirements:

• The commit message follows our guidelines: https://github.com/graycoreio/daffodil/blob/develop/CONTRIBUTING.md#commit
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

[ ] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Build related changes
[ ] CI related changes
[ ] Documentation content changes
[ ] Other... Please describe:

What is the current behavior?

Redundant styles on the why page page were added for IE 11 autoprefixer support.

Fixes: N/A

What is the new behavior?

Remove duplicate/unnecessary styles because we don't need IE11 support.

Does this PR introduce a breaking change?

[ ] Yes
[x] No

Other information