Really really delay SMS processing until sqlcipher migration completes

Blocking the SMS job on the screen lock isn't enough, since then
the job races against the migration.

Fixes #7390

src/org/thoughtcrime/securesms/jobs/requirements/SqlCipherMigrationRequirementProvider.java

@@ -0,0 +1,31 @@
+package org.thoughtcrime.securesms.jobs.requirements;
+
+
+import org.greenrobot.eventbus.EventBus;
+import org.greenrobot.eventbus.Subscribe;
+import org.greenrobot.eventbus.ThreadMode;
+import org.whispersystems.jobqueue.requirements.RequirementListener;
+import org.whispersystems.jobqueue.requirements.RequirementProvider;
+
+public class SqlCipherMigrationRequirementProvider implements RequirementProvider {
+
+  private RequirementListener listener;
+
+  public SqlCipherMigrationRequirementProvider() {
+    EventBus.getDefault().register(this);
+  }
+
+  @Override
+  public void setListener(RequirementListener listener) {
+    this.listener = listener;
+  }
+
+  @Subscribe(threadMode = ThreadMode.MAIN)
+  public void onEvent(SqlCipherNeedsMigrationEvent event) {
+    if (listener != null) listener.onRequirementStatusChanged();
+  }
+
+  public static class SqlCipherNeedsMigrationEvent {
+
+  }
+}