fix: remove edX support URL from login page (openedx#28593)

Author: zainab-amir

lms/static/js/student_account/views/LoginView.js

@@ -225,14 +225,13 @@
                         {
                             email: error.responseJSON.email,
                             platform_name: this.platform_name,
-                            support_url: 'https://support.edx.org/',
                             line_break: HtmlUtils.HTML('<br/>'),
                             strong_start: HtmlUtils.HTML('<strong>'),
                             strong_end: HtmlUtils.HTML('</strong>'),
                             anchorStart: HtmlUtils.HTML(
                                 StringUtils.interpolate(
                                     '<a href="{SupportUrl}">', {
-                                        SupportUrl: 'https://support.edx.org/'
+                                        SupportUrl: this.supportURL,
                                     }
                                 )
                             ),

openedx/core/djangoapps/site_configuration/helpers.py

@@ -134,18 +134,21 @@ def get_value(val_name, default=None, **kwargs):  # lint-amnesty, pylint: disabl
     else:
         configuration_value = default
 
-    # Attempt to perform a dictionary update using the provided default
-    # This will fail if the default value is not a dictionary
-    try:
-        value = dict(default)
-        value.update(configuration_value)
-
-    # If the dictionary update fails, just use the configuration value
-    # TypeError: default is not iterable (simple value or None)
-    # ValueError: default is iterable but not a dict (list, not dict)
-    # AttributeError: default does not have an 'update' method
-    except (TypeError, ValueError, AttributeError):
+    if default == '':
         value = configuration_value
+    else:
+        # Attempt to perform a dictionary update using the provided default
+        # This will fail if the default value is not a dictionary
+        try:
+            value = dict(default)
+            value.update(configuration_value)
+
+        # If the dictionary update fails, just use the configuration value
+        # TypeError: default is not iterable (simple value or None)
+        # ValueError: default is iterable but not a dict (list, not dict)
+        # AttributeError: default does not have an 'update' method
+        except (TypeError, ValueError, AttributeError):
+            value = configuration_value
 
     # Return the end result to the caller
     return value

openedx/core/djangoapps/site_configuration/tests/test_helpers.py

@@ -67,6 +67,10 @@ def test_get_value(self):
         # Test that the default value is returned if the value for the given key is not found in the configuration
         assert configuration_helpers.get_value('non_existent_name', 'dummy-default-value') == 'dummy-default-value'
 
+        # Test that correct default value is returned
+        assert configuration_helpers.get_value('non_existent_name', '') == ''
+        assert configuration_helpers.get_value('non_existent_name', None) is None
+
     @with_site_configuration(configuration=test_config)
     def test_get_dict(self):
         """