Fix dynamic type check which was too restrictive

// FREEBIE

SignalServiceKit/src/Messages/OWSIdentityManager.m

@@ -154,11 +154,13 @@ NSString *const kNSNotificationName_IdentityStateDidChange = @"kNSNotificationNa
     return identityKeyPair;
 }
 
+// This method should only be called from SignalProtocolKit, which doesn't know about YapDatabaseTransactions.
+// Whenever possible, prefer to call the strongly typed variant: `identityKeyPairWithTransaction:`.
 - (nullable ECKeyPair *)identityKeyPair:(nullable id)protocolContext
 {
-    OWSAssert([protocolContext isKindOfClass:[YapDatabaseReadWriteTransaction class]]);
+    OWSAssert([protocolContext isKindOfClass:[YapDatabaseReadTransaction class]]);
 
-    YapDatabaseReadWriteTransaction *transaction = protocolContext;
+    YapDatabaseReadTransaction *transaction = protocolContext;
 
     return [self identityKeyPairWithTransaction:transaction];
 }
@@ -449,7 +451,7 @@ NSString *const kNSNotificationName_IdentityStateDidChange = @"kNSNotificationNa
     OWSAssert(transaction);
 
     if ([[TSAccountManager localNumber] isEqualToString:recipientId]) {
-        ECKeyPair *_Nullable localIdentityKeyPair = [self identityKeyPair:transaction];
+        ECKeyPair *_Nullable localIdentityKeyPair = [self identityKeyPairWithTransaction:transaction];
 
         if ([localIdentityKeyPair.publicKey isEqualToData:identityKey]) {
             return YES;

SignalServiceKit/src/Messages/OWSMessageSender.m

@@ -1328,6 +1328,8 @@ NSString *const OWSMessageSenderRateLimitedException = @"RateLimitedException";
                 }
                 dispatch_semaphore_signal(sema);
             }];
+        // FIXME: Currently this happens within a readwrite transaction - meaning our read-write transaction blocks
+        // on a network request.
         dispatch_semaphore_wait(sema, DISPATCH_TIME_FOREVER);
         if (exception) {
             @throw exception;