Reduce the possible number of unique jobs to avoid crash.

Some devices have a limit of 100 unique JobScheduler jobs.
Previously we allowed up to 1,000. Given that we just need
_some_ job running, I lowered the limit to 75 to give us
some head room.

src/org/thoughtcrime/securesms/jobmanager/JobSchedulerScheduler.java

@@ -24,7 +24,7 @@ public class JobSchedulerScheduler implements Scheduler {
   private static final String PREF_NAME    = "JobSchedulerScheduler_prefs";
   private static final String PREF_NEXT_ID = "pref_next_id";
 
-  private static final int MAX_ID = 1000;
+  private static final int MAX_ID = 75;
 
   private final Application application;