fix: Enhanced announcement bar UI (light & dark mode improvement)

[Charul192]

What has changed?

• Enhanced the announcement bar UI for better alignment and visual consistency.
• Updated the light mode to a softer orange gradient for a clean, modern look.
• Redesigned the dark mode with a warm amber glow to improve visibility and match Keploy’s brand color.
• Added smooth gradient transitions and adjusted font-weight for better readability.
• Ensured the announcement bar blends well with both dark and light themes.

This PR Resolves #3002

Type of change

• Bug fix (non-breaking change which fixes an issue).

How Has This Been Tested?

• Ran npm run build → ✅ no build errors.
• Ran npm run serve → ✅ verified that the updated announcement bar renders correctly.
• Visually tested on: 💻 Desktop (Light + Dark Mode) 📱 Mobile (Chrome DevTools responsive view)
• Verified that the bar text is visible and gradient looks smooth in both themes.
• Screenshots(After) Light Mode: Dark Mode:

Checklist:

• My code follows the style guidelines of this project.
• I have performed a self-review of my own code.