Fix incremental backup exports.

Signal/src/ViewControllers/DebugUI/DebugUIBackup.m

@@ -77,6 +77,10 @@ NS_ASSUME_NONNULL_BEGIN
                                      actionBlock:^{
                                          [DebugUIBackup logBackupMetadataCache];
                                      }]];
+    [items addObject:[OWSTableItem itemWithTitle:@"Lazy Restore Attachments"
+                                     actionBlock:^{
+                                         [AppEnvironment.shared.backupLazyRestore runIfNecessary];
+                                     }]];
 
     return [OWSTableSection sectionWithTitle:self.name items:items];
 }

Signal/src/util/Backup/OWSBackupImportJob.m

@@ -175,7 +175,7 @@ NSString *const kOWSBackup_ImportDatabaseKeySpec = @"kOWSBackup_ImportDatabaseKe
         })
         .then(^{
             // Kick off lazy restore on main thread.
-            [self.backupLazyRestore runIfNecessary];
+            [self.backupLazyRestore clearCompleteAndRunIfNecessary];
 
             [self.profileManager fetchLocalUsersProfile];
 

Signal/src/util/Backup/OWSBackupLazyRestore.swift

@@ -53,6 +53,15 @@ public class BackupLazyRestore: NSObject {
 
     private let backgroundQueue = DispatchQueue.global(qos: .background)
 
+    @objc
+    public func clearCompleteAndRunIfNecessary() {
+        AssertIsOnMainThread()
+
+        isComplete = false
+
+        runIfNecessary()
+    }
+
     @objc
     public func runIfNecessary() {
         AssertIsOnMainThread()