chore: Remove sleep from when/then in e2e tests #35511

Job	Run time
changes	12s
Build & cache Go code	3m 13s
Ensure Go modules synchronicity	14s
Build, test & lint UI code	1m 29s
Check changes to generated code	4m 35s
Lint Go code	2m 58s
Run unit tests with -race for Go packages	8m 47s
Run end-to-end tests (v1.31.0, true)	37m 44s
Run end-to-end tests (v1.30.4, false)	37m 25s
Run end-to-end tests (v1.29.8, false)	36m 27s
Run unit tests for Go packages	4m 54s
Run end-to-end tests (v1.28.13, false)	37m 33s
E2E Tests - Composite result	1s
Process & analyze test artifacts	54s
	2h 56m 26s

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