Add div for inner extension helper text

The theme callback would set innerHTML on the header which wipes out the
dismiss button. With an inner div we can replace the inner HTML without
worrying about other elements in the header.

Closes #2799.

Author: code-asher

lib/vscode/src/vs/workbench/contrib/extensions/browser/extensionsViewlet.ts

@@ -466,11 +466,14 @@ export class ExtensionsViewPaneContainer extends ViewPaneContainer implements IE
 			helperHeader.style.fontWeight = '600';
 			helperHeader.style.padding = 'padding: 5px 16px';
 			helperHeader.style.position = 'relative';
+
+			const helperText = append(helperHeader, $('div'));
+
 			// We call this function because it gives us access to the current theme
 			// Then we can apply the link color to the links in the helper header
 			registerThemingParticipant((theme) => {
 				const linkColor = theme.getColor(textLinkForeground);
-				helperHeader.innerHTML = `
+				helperText.innerHTML = `
 				<div style="margin-bottom: 8px;">
 				<p style="margin-bottom: 0; display: flex; align-items: center"><span class="codicon codicon-warning" style="margin-right: 2px; color: #C4A103"></span>WARNING</p>
 				<p style="margin-top: 0; margin-bottom: 4px">
@@ -481,6 +484,7 @@ export class ExtensionsViewPaneContainer extends ViewPaneContainer implements IE
 				</div>
 						`;
 			});
+
 			const dismiss = append(helperHeader, $('span'));
 			dismiss.innerHTML = 'Dismiss';
 			dismiss.style.display = 'block';