[dev]: use random dir when running e2e tests

[jsjoeio]

Right now, we start code-server in the e2e tests CI job as is. Instead, we should start with a clean slate every time.

This will ensure consistency and confidence for our e2e tests.

Notes

• a random dir would let us parallelize
• create a random dir
• when loading code-server in the browser we include ?folder= so it opens in that directory
  • we can add this here: https://github.com/cdr/code-server/blob/main/test/utils/constants.ts#L1

[stale]

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