Description

Improves UX for invalid states during the subscription purchase flow.

Designs: 2MA6Bz3Vi36BOhuR9pitCU-fi-325_12576

Closes: #3760

Testing Instructions

1. Apply this patch.

curl -L https://github.com/user-attachments/files/20367006/plans-state.patch | git apply

2. Sign up.
3. During the onboarding flow, when you see the empty state, tap "Skip for now".
4. You should be able to skip purchasing a subscription.
5. Finish the onboarding process.
6. Go to the Profile tab.
7. Scroll to the bottom and tap the Pocket Cast Plus banner.
8. You should see the subscription plans empty state.
9. There should be no "Skip for now" button.
10. Tap "Try again".
11. The plans should load.
12. Try to purchase a subscription.
13. You should see an error snackbar.

Screenshots or Screencast

Empty state	Error state

Checklist

• If this is a user-facing change, I have added an entry in CHANGELOG.md
• Ensure the linter passes (./gradlew spotlessApply to automatically apply formatting/linting)
• I have considered whether it makes sense to add tests for my changes
• All strings that need to be localized are in modules/services/localization/src/main/res/values/strings.xml
• Any jetpack compose components I added or changed are covered by compose previews
• I have updated (or requested that someone edit) the spreadsheet to reflect any new or changed analytics.

I have tested any UI changes...

• with different themes
• with a landscape orientation
• with the device set to have a large display and font size
• for accessibility with TalkBack