Optimize TestReactivationSignalCache_Deduplication_* test timers

[Shivs11]

What changed?

Reduce drainage timer overrides from 10s grace + 30s refresh to 3s grace

• 10s refresh across all 4 cache dedup tests (StartWorkflow, SignalWithStart, UpdateOptions, Reset). This cuts each test from ~95s to ~41s while maintaining the critical invariant that wait durations match the overridden config values (see Flake Fix: In Reactivation Cache tests, wait for appropriate delays when confirming expected drainage status #9352). Remove now-unused testExtraLongVersionDrainageRefreshInterval.

Why?

• pace

How did you test it?

• built
• run locally and tested manually
• covered by existing tests
• added new unit test(s)
• added new functional test(s)

Potential risks

• none

---

Note

Low Risk
Test-only timing changes that reduce wait durations; main risk is increased flakiness on slow CI if the shorter drainage intervals are insufficient.

Overview
Speeds up the TestReactivationSignalCache_Deduplication_* functional tests by reducing overridden drainage timers (using 3s visibility grace and 10s refresh) and updating the corresponding wait windows.

Removes the now-unused testExtraLongVersionDrainageRefreshInterval constant.

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