[Feature details] Observation sync sometimes times out
The timeout may need to be increased for slower internet connections:

```
2021-06-04 11:45:26.204 2125-9557/com.google.android.gnd E/ObservationRepository: Observation sync timed out
    java.util.concurrent.TimeoutException: The source did not signal an event for 5 seconds and has been terminated.
        at io.reactivex.internal.operators.single.SingleTimeout$TimeoutMainObserver.run(SingleTimeout.java:123)
        at io.reactivex.internal.schedulers.ScheduledDirectTask.call(ScheduledDirectTask.java:38)
        at io.reactivex.internal.schedulers.ScheduledDirectTask.call(ScheduledDirectTask.java:26)
        at java.util.concurrent.FutureTask.run(FutureTask.java:266)
        at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:301)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
        at java.lang.Thread.run(Thread.java:923)
```
diff --git a/gnd/src/main/java/com/google/android/gnd/repository/ObservationRepository.java b/gnd/src/main/java/com/google/android/gnd/repository/ObservationRepository.java
index 31253940a..3a438ffe9 100644
--- a/gnd/src/main/java/com/google/android/gnd/repository/ObservationRepository.java
+++ b/gnd/src/main/java/com/google/android/gnd/repository/ObservationRepository.java
@@ -45,7 +45,7 @@ import timber.log.Timber;
  */
 public class ObservationRepository {
 
-  private static final long LOAD_REMOTE_OBSERVATIONS_TIMEOUT_SECS = 5;
+  private static final long LOAD_REMOTE_OBSERVATIONS_TIMEOUT_SECS = 15;
 
   private final LocalDataStore localDataStore;
   private final RemoteDataStore remoteDataStore;
diff --git a/gnd/src/main/java/com/google/android/gnd/repository/ProjectRepository.java b/gnd/src/main/java/com/google/android/gnd/repository/ProjectRepository.java
index 727e6568f..0c0965555 100644
--- a/gnd/src/main/java/com/google/android/gnd/repository/ProjectRepository.java
+++ b/gnd/src/main/java/com/google/android/gnd/repository/ProjectRepository.java
@@ -53,7 +53,7 @@ import timber.log.Timber;
 @Singleton
 public class ProjectRepository {
 
-  private static final long LOAD_REMOTE_PROJECT_TIMEOUT_SECS = 5;
+  private static final long LOAD_REMOTE_PROJECT_TIMEOUT_SECS = 15;
   private static final long LOAD_REMOTE_PROJECT_SUMMARIES_TIMEOUT_SECS = 30;
 
   private final InMemoryCache cache;
['gnd/src/main/java/com/google/android/gnd/repository/ObservationRepository.java', 'gnd/src/main/java/com/google/android/gnd/repository/ProjectRepository.java']