isobmff: fix DREF unittest

Tested:
```
$ make test
Running tests...
/usr/local/lib64/python3.13/site-packages/cmake/data/bin/ctest
Test project isobmff/build
    Start 1: DREF_unittest
1/8 Test #1: DREF_unittest ....................   Passed    0.00 sec
    Start 2: FTYP_unittest
2/8 Test #2: FTYP_unittest ....................   Passed    0.00 sec
    Start 3: HDLR_unittest
3/8 Test #3: HDLR_unittest ....................   Passed    0.00 sec
    Start 4: MDHD_unittest
4/8 Test #4: MDHD_unittest ....................   Passed    0.00 sec
    Start 5: META_unittest
5/8 Test #5: META_unittest ....................   Passed    0.00 sec
    Start 6: MVHD_unittest
6/8 Test #6: MVHD_unittest ....................   Passed    0.00 sec
    Start 7: Parser_unittest
7/8 Test #7: Parser_unittest ..................   Passed    0.00 sec
    Start 8: TKHD_unittest
8/8 Test #8: TKHD_unittest ....................   Passed    0.00 sec

100% tests passed, 0 tests failed out of 8

Total Test time (real) =   0.03 sec
```

Author: chemag

src/DREF.cpp

@@ -87,7 +87,7 @@ namespace ISOBMFF
 
         FullBox::ReadData(parser, stream);
 
-        stream.Seek(8); // Move to the position after the 'dref' header
+        // auto entry_count =
         stream.ReadBigEndianUInt32();
         container.ReadData(parser, stream);
 

test/DREF_unittest.cpp

@@ -22,9 +22,9 @@ class ISOBMFFDREFTest : public ::testing::Test {
   const std::vector<uint8_t> &buffer = {
       // following example input is from a sample .mp4 video file
       // dref size: 28 bytes
-      0x00, 0x00, 0x00, 0x1c,
+      // 0x00, 0x00, 0x00, 0x1c,
       // dref
-      0x64, 0x72, 0x65, 0x66,
+      // 0x64, 0x72, 0x65, 0x66,
       // dref content:
       0x00, 0x00, 0x00, 0x00,
       0x00, 0x00, 0x00, 0x01,
@@ -52,7 +52,7 @@ class ISOBMFFDREFTest : public ::testing::Test {
   ASSERT_NE(dref, nullptr) << "Failed to cast to DREF";
 
   EXPECT_EQ(dref->GetVersion(), 0) << "Unexpected DREF version";
-  EXPECT_EQ(dref->GetFlags(), 28) << "Unexpected DREF flags";
+  EXPECT_EQ(dref->GetFlags(), 0) << "Unexpected DREF flags";
 
   // Validate sub-boxes inside DREF
   std::vector<std::shared_ptr<Box>> boxes = dref->GetBoxes();