Heartrate: ignore "0" if sent from sensor as this is an invalid value.

On import "0" is ignored.

src/main/java/de/dennisguse/opentracks/data/CustomSQLiteOpenHelper.java

@@ -29,7 +29,7 @@ class CustomSQLiteOpenHelper extends SQLiteOpenHelper {
 
     private static final String TAG = CustomSQLiteOpenHelper.class.getSimpleName();
 
-    private static final int DATABASE_VERSION = 42;
+    private static final int DATABASE_VERSION = 43;
 
     private final Context context;
 
@@ -86,6 +86,7 @@ class CustomSQLiteOpenHelper extends SQLiteOpenHelper {
                 case 40 -> upgradeFrom39to40(db);
                 case 41 -> upgradeFrom40to41(db);
                 case 42 -> upgradeFrom41to42(db);
+                case 43 -> upgradeFrom42to43(db);
                 default -> throw new RuntimeException("Not implemented: upgrade to " + toVersion);
             }
         }
@@ -115,6 +116,7 @@ class CustomSQLiteOpenHelper extends SQLiteOpenHelper {
                 case 39 -> downgradeFrom40to39(db);
                 case 40 -> downgradeFrom41to40(db);
                 case 41 -> downgradeFrom42to41(db);
+                case 42 -> downgradeFrom43to42(db);
                 default -> throw new RuntimeException("Not implemented: downgrade to " + toVersion);
             }
         }
@@ -794,4 +796,18 @@ class CustomSQLiteOpenHelper extends SQLiteOpenHelper {
         db.setTransactionSuccessful();
         db.endTransaction();
     }
+
+    private void upgradeFrom42to43(SQLiteDatabase db) {
+        db.beginTransaction();
+
+        db.execSQL("UPDATE trackpoints SET heartrate = null WHERE heartrate = 0.0");
+
+
+        db.setTransactionSuccessful();
+        db.endTransaction();
+    }
+
+    private void downgradeFrom43to42(SQLiteDatabase db) {
+        // Downgrade not possible: invalid data replaced with null.
+    }
 }