Simplify push notification flow by using locally stored values for pending pushes (#6258)

* Create `PushRequest` in push history DB: this will be used to store requests for push notifications, either pending or completed ones.

* Rename `WorkManagerRequest` to `WorkManagerRequestBuilder`: make its `build` method return a list of `WorkManagerRequestWrapper`, which can be used to enqueue normal or unique workers.

* Rename `PerformDatabaseVacuumRequestBuilder` and adapt it to the new API.

* Adjust other components using `WorkManagerRequest`.

* Replace `SyncNotificationWorkManagerRequestBuilder` with `SyncPendingNotificationsRequestBuilder` and `FetchNotificationsWorker` with `FetchPendingNotificationsWorker`: this new pair of request builder and worker allow enqueuing requests for a session id and, once the worker runs, retrieve all the pending request data and use it to fetch the associated events. This simplifies quite a bit how this data had to be passed or grouped, since it's no longer necessary to do so

* Add new methods to `PushHistoryService` to modify the `PushDatabase`:

- insertOrUpdatePushRequest
- insertOrUpdatePushRequests
- getPendingPushRequests
- removeOldPushRequests

* Make `PushHandler` just handle incoming pushes: those will be inserted into the pending push request table in DB, then handled by the new worker. Once the process finished, a new `NotificationResultProcessor` will handle the results and what needs to be done with them (call ringing, displaying notifications, etc.)

* Add `requestType` optional parameter to `WorkManagerScheduler.cancel` so we can decide to only cancel some kinds of requests.

* Add migration to remove existing work manager requests for fetching notifications, since the previous worker class no longer exists.

libraries/push/impl/src/main/sqldelight/io/element/android/libraries/push/impl/db/PushHistory.sq

@@ -17,6 +17,5 @@ INSERT INTO PushHistory VALUES ?;
 removeAll:
 DELETE FROM PushHistory;
 
--- add query to keep only the last x entries
 removeOldest:
 DELETE FROM PushHistory WHERE rowid NOT IN (SELECT rowid FROM PushHistory ORDER BY pushDate DESC LIMIT ?);

libraries/push/impl/src/main/sqldelight/io/element/android/libraries/push/impl/db/PushRequest.sq

@@ -0,0 +1,24 @@
+CREATE TABLE PushRequest (
+    pushDate INTEGER NOT NULL,
+    providerInfo TEXT NOT NULL,
+    eventId TEXT NOT NULL,
+    roomId TEXT NOT NULL,
+    sessionId TEXT NOT NULL,
+    status INTEGER NOT NULL DEFAULT 0,
+    retries INTEGER NOT NULL DEFAULT 0,
+    PRIMARY KEY(sessionId, eventId)
+);
+
+CREATE INDEX PushRequestSessionAndStatus ON PushRequest (sessionId, status);
+
+selectAllPendingForSession:
+SELECT * FROM PushRequest WHERE status = 0 AND sessionId = ? AND pushDate > ? ORDER BY pushDate ASC;
+
+insertPushRequest:
+INSERT OR REPLACE INTO PushRequest VALUES ?;
+
+removeAll:
+DELETE FROM PushRequest;
+
+removeOldest:
+DELETE FROM PushRequest WHERE rowid NOT IN (SELECT rowid FROM PushRequest ORDER BY pushDate DESC LIMIT ?);

libraries/push/impl/src/main/sqldelight/migrations/1.sqm

@@ -0,0 +1,14 @@
+-- Migrate DB from version 1
+
+CREATE TABLE PushRequest (
+    pushDate INTEGER NOT NULL,
+    providerInfo TEXT NOT NULL,
+    eventId TEXT NOT NULL,
+    roomId TEXT NOT NULL,
+    sessionId TEXT NOT NULL,
+    status INTEGER NOT NULL DEFAULT 0,
+    retries INTEGER NOT NULL DEFAULT 0,
+    PRIMARY KEY(sessionId, eventId)
+);
+
+CREATE INDEX PushRequestSessionAndStatus ON PushRequest (sessionId, status);