test(core): Allow repeated scopes storage set calls in SentryTest (#6359)

The custom storage mock always returns null from get(), so the BackpressureMonitor health check, scheduled 500ms after init, forks the root scopes and calls set() again. On slow runners that landed before verify and failed the test with TooManyActualInvocations.

Co-authored-by: sentry-junior[bot] <264270552+sentry-junior[bot]@users.noreply.github.com>
Co-authored-by: Nelson Osacky <nelson.osacky@sentry.io>

Author: sentry-junior[bot]

sentry/src/test/java/io/sentry/SentryTest.kt

@@ -1879,7 +1879,9 @@ class SentryTest {
     }
 
     verify(customStorage).init()
-    verify(customStorage).set(any())
+    // get() always returns null here, so every later getCurrentScopes() call forks the root scopes
+    // and calls set() again, e.g. the BackpressureMonitor health check on the executor
+    verify(customStorage, atLeastOnce()).set(any())
   }
 
   @Test