ci: Downgrade runners to ubuntu-20.04

[lforst]

#15219 was a bit eager. We cannot have different runners for normal jobs and our large runners as the browser binaries will be different.

We need to:

• add a large runner image that runs on 22.04
• bump all of the runner images to 22.04

[codecov]

❌ 417 Tests Failed:

Tests completed	Failed	Passed	Skipped
1138	417	721	303

View the top 3 failed test(s) by shortest run time

tracing/metrics/handlers-lcp/test.ts should capture metrics for LCP instrumentation handlers

Stack Traces | 0.001s run time

test.ts:10:11 should capture metrics for LCP instrumentation handlers

tracing/metrics/pageload-measure-spans/test.ts should add browser-related spans to pageload transaction

Stack Traces | 0.003s run time

test.ts:8:11 should add browser-related spans to pageload transaction

replay/slowClick/clickTargets/test.ts slow click is captured for inputButton

Stack Traces | 0.006s run time

test.ts:33:15 slow click is captured for inputButton

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