Fix flaky widget-pip-close.spec.ts end to end test

[germain-gg]

I have noticed multiple PRs where widget-pip-close.spec.ts has been flaky

matrix-org/matrix-react-sdk#9328 for instance

[t3chguy]

https://dashboard.cypress.io/projects/ppvnzg/runs/4345/overview/7958767d-7cd3-4714-a53b-86bc9f1a9a6a

[t3chguy]

Duplicate of #23286