Remove unused extends from some CSS pages

Simon Knoxrequested to merge
psi-no-extend-2 into master

What does this MR do?

Remove some instances of extend from CSS for #323021 (closed)

using extend leads to unpredictable CSS output, and has some build time perf problems on new libsass

For one deleted entirely
For one replaced with the relevant CSS rules
For one added the class directly to HTML

Edited by Simon Knox

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