fix: Clear VerifiedOneOnOneChats config on backup (#4681)

If the user makes a backup from a UI that supports the experimental verified 1:1 chats (e.g. nightly Android) and imports it into a UI that doesn't, then this config should be cleared.

We already talked about this a long time ago after @Simon-Laux noticed this problem, but I think we didn't actually solve it back then?

Best to review with whitespace changes disabled.

src/imex.rs

@@ -771,6 +771,11 @@ async fn export_database(context: &Context, dest: &Path, passphrase: String) ->
             let res = conn
                 .query_row("SELECT sqlcipher_export('backup')", [], |_row| Ok(()))
                 .context("failed to export to attached backup database");
+            conn.execute(
+                "UPDATE backup.config SET value='0' WHERE keyname='verified_one_on_one_chats';",
+                [],
+            )
+            .ok(); // If verified_one_on_one_chats was not set, this errors, which we ignore
             conn.execute("DETACH DATABASE backup", [])
                 .context("failed to detach backup database")?;
             res?;
@@ -880,10 +885,16 @@ mod tests {
 
     #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
     async fn test_export_and_import_backup() -> Result<()> {
+        for set_verified_oneonone_chats in [true, false] {
             let backup_dir = tempfile::tempdir().unwrap();
 
             let context1 = TestContext::new_alice().await;
             assert!(context1.is_configured().await?);
+            if set_verified_oneonone_chats {
+                context1
+                    .set_config_bool(Config::VerifiedOneOnOneChats, true)
+                    .await?;
+            }
 
             let context2 = TestContext::new().await;
             assert!(!context2.is_configured().await?);
@@ -928,7 +939,19 @@ mod tests {
                 context2.get_config(Config::Addr).await?,
                 Some("alice@example.org".to_string())
             );
-
+            assert_eq!(
+                context2
+                    .get_config_bool(Config::VerifiedOneOnOneChats)
+                    .await?,
+                false
+            );
+            assert_eq!(
+                context1
+                    .get_config_bool(Config::VerifiedOneOnOneChats)
+                    .await?,
+                set_verified_oneonone_chats
+            );
+        }
         Ok(())
     }