end-to-end tests broken trying to read stack of undefined

[turt2live]

firstly, what are we throwing that isn't an error and secondly, here's the logs:

(node:942) UnhandledPromiseRejectionWarning: Error: Evaluation failed: TypeError: Cannot read properties of null (reading 'stack')
    at __puppeteer_evaluation_script__:2:34
    at ExecutionContext._evaluateInternal (/__w/matrix-react-sdk/matrix-react-sdk/test/end-to-end-tests/node_modules/puppeteer/lib/cjs/puppeteer/common/ExecutionContext.js:221:19)
    at runMicrotasks (<anonymous>)
    at processTicksAndRejections (internal/process/task_queues.js:95:5)
    at async ExecutionContext.evaluate (/__w/matrix-react-sdk/matrix-react-sdk/test/end-to-end-tests/node_modules/puppeteer/lib/cjs/puppeteer/common/ExecutionContext.js:110:16)
    at async JSHandle.evaluate (/__w/matrix-react-sdk/matrix-react-sdk/test/end-to-end-tests/node_modules/puppeteer/lib/cjs/puppeteer/common/JSHandle.js:103:16)
(node:942) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 10)

Almost certainly related to matrix-org/matrix-react-sdk#7959