Do not report detekt LargeClass issues on test classes (#7713)

detekt's default configuration excludes test source sets from
`TooManyFunctions` and `StringLiteralDuplication`, but not from
`LargeClass`, so large test classes were reported and had to carry a
`@Suppress("LargeClass")` annotation.

Add the same kind of exclusion to the `LargeClass` rule in
`tools/detekt/detekt.yml` and remove the 24 now-redundant suppressions
from test files. The two remaining suppressions are in production code,
where the rule still applies.

Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>

libraries/push/impl/src/test/kotlin/io/element/android/libraries/push/impl/notifications/DefaultNotifiableEventResolverTest.kt

@@ -69,7 +69,6 @@ import org.junit.Test
 import org.robolectric.RuntimeEnvironment
 import org.robolectric.annotation.Config
 
-@Suppress("LargeClass")
 class DefaultNotifiableEventResolverTest : RobolectricTest() {
     @Test
     fun `resolve event no session`() = runTest {

libraries/push/impl/src/test/kotlin/io/element/android/libraries/push/impl/push/DefaultPushHandlerTest.kt

@@ -52,7 +52,6 @@ import kotlin.time.Duration.Companion.milliseconds
 
 private const val A_PUSHER_INFO = "info"
 
-@Suppress("LargeClass")
 class DefaultPushHandlerTest {
     @Test
     fun `check handleInvalid behavior`() = runTest {