feat: Improve scrolling experience on Discover title

[HamzaIsrar12]

Description

LEARNER-9514

• Enhance the Scrolling Experience for the Discover Section
• Renamed the title from Discover to Explore the Catalog
• Defaulted the title to be hidden in favour of the web view's internal title
• The title will only be displayed upon scrolling
• Ensured consistency between the discovery experience for both guest users and logged-in users

[codecov[bot]]

Codecov Report

:exclamation: No coverage uploaded for pull request base (app_nav@8366f1f). Click here to learn what that means. Patch has no changes to coverable lines.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## app_nav #1816 +/- ## ========================================= Coverage ? 1.10% Complexity ? 137 ========================================= Files ? 540 Lines ? 25830 Branches ? 3255 ========================================= Hits ? 286 Misses ? 25517 Partials ? 27 ```

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