chore: fix cypress scripts on windows

[flotwig]

• Closes Developing on windows has a broken workflow (or contributing instructions incorrect) #8783

Removed bash-isms that won't work on Windows cmd.exe.

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[cypress]

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Test summary

9388 • 0 • 119 • 3 • 1

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Run details

Project	cypress
Status	Passed
Commit	38b01cb
Started	Mar 16, 2021 2:31 AM
Ended	Mar 16, 2021 2:44 AM
Duration	12:47 💡
OS	Linux Debian - 10.5
Browser	Multiple

View run in Cypress Dashboard ➡️

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Flakiness

	cypress/integration/retries.ui.spec.js		1
1	runner/cypress retries.ui.spec > opens attempt on each attempt failure for the screenshot, and closes after test passes

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[dmtrKovalenko]

It looks like really weird workaround, I don't understand why this might not work on windows but I trust that this is required :)

[flotwig]

cmd.exe doesn't support substituting commands like that