chore: Update c2pa-native-version.txt to use c2pa v0.75.16 (#224)

* chore: Update c2pa-native-version.txt

* fix: Update test_unit_tests.py

* Update test_unit_tests.py

* Update c2pa-native-version.txt

* Update test_unit_tests.py

* Update c2pa-native-version.txt

* fix: Remove obsolete test

* fix: Prep for 0.75.16

* fix: Retrigger all tests

Author: tmathern

c2pa-native-version.txt

@@ -1 +1 @@
-c2pa-v0.75.10
+c2pa-v0.75.16

tests/test_unit_tests.py

@@ -45,7 +45,7 @@ def load_test_settings_json():
     """
     Load default (legacy) trust configuration test settings from a
     JSON config file and return its content as JSON-compatible dict.
-    The return value is used to load settings.
+    The return value is used to load settings (thread_local) in tests.
 
     Returns:
         dict: The parsed JSON content as a Python dictionary (JSON-compatible).
@@ -68,7 +68,7 @@ def load_test_settings_json():
 class TestC2paSdk(unittest.TestCase):
     def test_sdk_version(self):
         # This test verifies the native libraries used match the expected version
-        self.assertIn("0.75.10", sdk_version())
+        self.assertIn("0.75.16", sdk_version())
 
 
 class TestReader(unittest.TestCase):
@@ -4374,11 +4374,6 @@ def tearDown(self):
         if os.path.exists(self.temp_data_dir):
             shutil.rmtree(self.temp_data_dir)
 
-    def test_invalid_settings_str(self):
-        """Test loading a malformed settings string."""
-        with self.assertRaises(Error):
-            load_settings(r'{"verify": { "remote_manifest_fetch": false }')
-
     def test_read_ingredient_file(self):
         """Test reading a C2PA ingredient from a file."""
         # Test reading ingredient from file with data_dir