Prompt to Confirm Discarding Post on Back Navigation

[Shruti-1910]

Description:

Currently, when a user is in the process of creating a post (selecting photos and writing a caption) and accidentally clicks the back button, the app navigates back to the home screen without any warning. The app should prompt users to confirm whether they want to discard the post or not when they attempt to navigate away from the post creation screen.

Expected Behavior:

• When a user is creating a post and clicks the back button, a confirmation pop-up should appear asking if they want to discard the post or continue editing.
• If the user chooses to discard, the app should navigate back to the home screen and discard both the selected photos and caption.
• If the user chooses to continue editing, they should remain on the post creation screen with their selected photos and caption intact.

Acceptance Criteria:

1. User Interface:

• A confirmation pop-up should appear when the back button is pressed during post creation.
• The pop-up should contain a clear message (e.g., "Are you sure you want to discard this post?") and two options: "Discard" and "Continue Editing".
• The pop-up design should be consistent with the overall app design.

2. Functionality:

• The back navigation should be intercepted during post creation to trigger the confirmation pop-up.
• Selecting "Discard" should navigate back to the home screen and clear both the selected photos and caption.
• Selecting "Continue Editing" should dismiss the pop-up and keep the user on the post creation screen with all content preserved.