Add kotlin Result to WellKnownThreadSafety -[]

`Result<T>` is an immutable wrapper over a `T` in the case of success, or `Throwable` in the case of an error.

Kotlin docs - https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-result/

TAP train - []

PiperOrigin-RevId: 654794053

core/src/main/java/com/google/errorprone/bugpatterns/threadsafety/WellKnownThreadSafety.java

@@ -149,6 +149,7 @@ private static ImmutableMap<String, AnnotationInfo> buildThreadSafeClasses(
         .add("kotlinx.coroutines.flow.MutableStateFlow", "T")
         .add("kotlinx.coroutines.sync.Mutex")
         .add("kotlinx.coroutines.sync.Semaphore")
+        .add("kotlin.Result", "T")
         .add("kotlin.Unit")
         .add("org.bouncycastle.cms.CMSSignedData")
         .add("org.bouncycastle.pkcs.PKCS10CertificationRequest")