Updates the commit SHA the `material-unit-tests` CircleCI
job runs against. We need to include a commit that makes
the node module installation more determinisitc (i.e. ensuring
that `tsickle` is always hoisted at the node module root).

https://github.com/angular/components/commit/31a50f7ad2947d9ceba99a64717ffa263a2a1d56

PR Close #33717