Replace text-secondary with gl-text-subtle

Replace `text-secondary` class with `gl-text-subtle` class
Update `GlIcon` to use `variant="subtle"
Update IDE styles to remove `text-secondary` style overrides
Add contextual utility class to apply `gl-font-normal`

ee/spec/frontend/boards/components/board_scope_spec.js

@@ -52,6 +52,6 @@ describe('BoardScope', () => {
     ${false}     | ${'Board scope affects which epics are displayed for anyone who visits this board'}
   `('displays $text when isIssueBoard is $isIssueBoard', ({ isIssueBoard, text }) => {
     mountComponent({ isIssueBoard });
-    expect(wrapper.find('p.text-secondary').text()).toEqual(text);
+    expect(wrapper.find('p.gl-text-subtle').text()).toEqual(text);
   });
 });

spec/frontend/design_management/components/list/__snapshots__/item_spec.js.snap

@@ -2,10 +2,9 @@
 
 exports[`Design management list item component when item appears in view after image is loaded renders media broken icon when image onerror triggered 1`] = `
 <gl-icon-stub
-  class="text-secondary"
   name="media-broken"
   size="32"
-  variant="current"
+  variant="subtle"
 />
 `;
 

spec/frontend/issuable/components/related_issuable_item_spec.js

@@ -80,7 +80,7 @@ describe('RelatedIssuableItem', () => {
   it('does not render token state', () => {
     mountComponent();
 
-    expect(wrapper.find('.text-secondary svg').exists()).toBe(false);
+    expect(wrapper.find('.gl-text-subtle svg').exists()).toBe(false);
   });
 
   it('does not render remove button', () => {

spec/frontend/jira_import/components/__snapshots__/jira_import_form_spec.js.snap

@@ -130,7 +130,7 @@ exports[`JiraImportForm table body shows correct information in each cell 1`] =
                   />
                 </div>
                 <li
-                  class="gl-dropdown-text text-secondary"
+                  class="gl-dropdown-text gl-text-subtle"
                   role="presentation"
                 >
                   <p
@@ -231,7 +231,7 @@ exports[`JiraImportForm table body shows correct information in each cell 1`] =
                   />
                 </div>
                 <li
-                  class="gl-dropdown-text text-secondary"
+                  class="gl-dropdown-text gl-text-subtle"
                   role="presentation"
                 >
                   <p

spec/frontend/work_items/components/design_management/__snapshots__/design_item_spec.js.snap

@@ -2,10 +2,9 @@
 
 exports[`Design item component when item appears in view after image is loaded renders media broken icon when image onerror triggered 1`] = `
 <gl-icon-stub
-  class="text-secondary"
   name="media-broken"
   size="32"
-  variant="current"
+  variant="subtle"
 />
 `;