Preserve 'use-client' directives during rollup

[rjwills28]

Previously we were getting a lot of warnings thrown during rollup that the use client directive from the 'mui' package were ignored:

(!) node_modules/@mui/styled-engine/GlobalStyles/GlobalStyles.js (1:0): Module level directives cause errors when bundled, "use client" in "node_modules/@mui/styled-engine/GlobalStyles/GlobalStyles.js" was ignored.
/cs-web-lib/node_modules/@mui/styled-engine/GlobalStyles/GlobalStyles.js:1:0
1: 'use client';
   ^
2: 
3: import * as React from 'react';

This use client directive is used by the mui package to mark the module as client code and therefore should probably be preserved during the rollup. There is a package rollup-preserve-directives that can do this so I have added this and configured it in the rollup.config file.

[abigailalexander]

Tested that the rollup warnings are gone and the package installs as usual, all works. LGTM!