Fix call link export crash.

app/src/main/java/org/thoughtcrime/securesms/backup/v2/database/CallLinkTableBackupExtensions.kt

@@ -6,6 +6,7 @@
 package org.thoughtcrime.securesms.backup.v2.database
 
 import android.database.Cursor
+import okio.ByteString
 import okio.ByteString.Companion.toByteString
 import org.signal.core.util.select
 import org.signal.ringrtc.CallLinkRootKey
@@ -63,8 +64,8 @@ class BackupCallLinkIterator(private val cursor: Cursor) : Iterator<BackupRecipi
     return BackupRecipient(
       id = callLink.recipientId.toLong(),
       callLink = CallLink(
-        rootKey = callLink.credentials!!.linkKeyBytes.toByteString(),
-        adminKey = callLink.credentials.adminPassBytes?.toByteString(),
+        rootKey = callLink.credentials?.linkKeyBytes?.toByteString() ?: ByteString.EMPTY,
+        adminKey = callLink.credentials?.adminPassBytes?.toByteString(),
         name = callLink.state.name,
         expirationMs = callLink.state.expiration.toEpochMilli(),
         restrictions = callLink.state.restrictions.toBackup()

app/src/main/java/org/thoughtcrime/securesms/database/CallLinkTable.kt

@@ -415,10 +415,12 @@ class CallLinkTable(context: Context, databaseHelper: SignalDatabase) : Database
       return CallLink(
         recipientId = data.requireLong(RECIPIENT_ID).let { if (it > 0) RecipientId.from(it) else RecipientId.UNKNOWN },
         roomId = CallLinkRoomId.DatabaseSerializer.deserialize(data.requireNonNullString(ROOM_ID)),
-        credentials = CallLinkCredentials(
-          linkKeyBytes = data.requireNonNullBlob(ROOT_KEY),
-          adminPassBytes = data.requireBlob(ADMIN_KEY)
-        ),
+        credentials = data.requireBlob(ROOT_KEY)?.let { linkKey ->
+          CallLinkCredentials(
+            linkKeyBytes = linkKey,
+            adminPassBytes = data.requireBlob(ADMIN_KEY)
+          )
+        },
         state = SignalCallLinkState(
           name = data.requireNonNullString(NAME),
           restrictions = data.requireInt(RESTRICTIONS).mapToRestrictions(),