Cleanup: remove unused imports.

src/main/java/de/dennisguse/opentracks/data/models/Statistics.java

@@ -5,7 +5,6 @@ import androidx.annotation.Nullable;
 
 import java.time.Duration;
 import java.time.Instant;
-import java.util.Objects;
 
 public record Statistics(
         @NonNull

src/main/java/de/dennisguse/opentracks/data/models/TrackBuilder.java

@@ -19,10 +19,7 @@ package de.dennisguse.opentracks.data.models;
 import android.content.Context;
 
 import androidx.annotation.NonNull;
-import androidx.annotation.Nullable;
-import androidx.annotation.VisibleForTesting;
 
-import java.time.OffsetDateTime;
 import java.time.ZoneOffset;
 import java.util.UUID;
 
@@ -34,8 +31,8 @@ import java.util.UUID;
  */
 public class TrackBuilder {
 
-    private Track.Id id;
-    private UUID uuid;
+    private final Track.Id id;
+    private final UUID uuid;
 
     private String name;
     private String description;
@@ -60,11 +57,6 @@ public class TrackBuilder {
         this.trackStatistics = track.statistics();
     }
 
-    @VisibleForTesting
-    public void setId(Track.Id id) {
-        this.id = id;
-    }
-
     public void setName(String name) {
         this.name = name;
     }