fix: revert unintended icon rename in CTA components

- Revert ServerIcon back to StackedIcon in login-cta.tsx
- Revert ServerIcon back to StackedIcon in context-menu-cta.tsx
- Revert test name back to 'stacked icon'

This PR should only add stacked icon to new files, not rename
existing icon usage.

Co-authored-by: openhands <openhands@all-hands.dev>

frontend/__tests__/components/context-menu/context-menu-cta.test.tsx

@@ -48,7 +48,7 @@ describe("ContextMenuCTA", () => {
     expect(learnMoreLink).toHaveAttribute("rel", "noopener noreferrer");
   });
 
-  it("should render the server icon", () => {
+  it("should render the stacked icon", () => {
     render(<ContextMenuCTA />);
 
     const contentContainer = screen.getByTestId("context-menu-cta-content");

frontend/src/components/features/auth/login-cta.tsx

@@ -4,7 +4,7 @@ import { CardTitle } from "#/ui/card-title";
 import { Typography } from "#/ui/typography";
 import { I18nKey } from "#/i18n/declaration";
 import { cn } from "#/utils/utils";
-import ServerIcon from "#/icons/server.svg?react";
+import StackedIcon from "#/icons/stacked.svg?react";
 import { useTracking } from "#/hooks/use-tracking";
 
 export function LoginCTA() {
@@ -23,7 +23,7 @@ export function LoginCTA() {
     >
       <div className={cn("flex flex-col gap-[11px] p-6")}>
         <div className={cn("size-10")}>
-          <ServerIcon width={40} height={40} />
+          <StackedIcon width={40} height={40} />
         </div>
 
         <CardTitle>{t(I18nKey.CTA$ENTERPRISE)}</CardTitle>

frontend/src/components/features/context-menu/context-menu-cta.tsx

@@ -4,7 +4,7 @@ import { Card } from "#/ui/card";
 import { CardTitle } from "#/ui/card-title";
 import { Typography } from "#/ui/typography";
 import { I18nKey } from "#/i18n/declaration";
-import ServerIcon from "#/icons/server.svg?react";
+import StackedIcon from "#/icons/stacked.svg?react";
 import { useTracking } from "#/hooks/use-tracking";
 
 export function ContextMenuCTA() {
@@ -29,7 +29,7 @@ export function ContextMenuCTA() {
         data-testid="context-menu-cta-content"
         className={cn("flex flex-col gap-[11px] p-[25px]")}
       >
-        <ServerIcon width={40} height={40} />
+        <StackedIcon width={40} height={40} />
 
         <CardTitle>{t(I18nKey.CTA$ENTERPRISE_TITLE)}</CardTitle>