fix: allow units sourced from libraries to update their settings (#1863)

src/course-unit/header-title/HeaderTitle.jsx

@@ -89,7 +89,6 @@ const HeaderTitle = ({
           className="flex-shrink-0"
           iconAs={SettingsIcon}
           onClick={openConfigureModal}
-          disabled={readOnly}
         />
         <ConfigureModal
           isOpen={isConfigureModalOpen}

src/course-unit/header-title/HeaderTitle.test.jsx

@@ -76,7 +76,7 @@ describe('<HeaderTitle />', () => {
     expect(getByRole('button', { name: messages.altButtonSettings.defaultMessage })).toBeEnabled();
   });
 
-  it('Units sourced from upstream show a disabled edit form and config menu', async () => {
+  it('Units sourced from upstream show a disabled edit button', async () => {
     // Override mock unit with one sourced from an upstream library
     axiosMock = new MockAdapter(getAuthenticatedHttpClient());
     axiosMock
@@ -92,7 +92,7 @@ describe('<HeaderTitle />', () => {
     const { getByRole } = renderComponent();
 
     expect(getByRole('button', { name: messages.altButtonEdit.defaultMessage })).toBeDisabled();
-    expect(getByRole('button', { name: messages.altButtonSettings.defaultMessage })).toBeDisabled();
+    expect(getByRole('button', { name: messages.altButtonSettings.defaultMessage })).toBeEnabled();
   });
 
   it('calls toggle edit title form by clicking on Edit button', () => {