[feature/MOB-585] - Update generic errors for the purchase flow

[joaopmgouveia]

What does this PR do?

This PR changes the generic error dialogs shown in the purchase flow with an update one (the one shown in Top Up)

Database changed?

No

Where should the reviewer start?

• [ ] IabActivity.kt
• [ ] generic_purchase_error_fragment.xml

How should this be manually tested?

Flow on how to test this or QA Tickets related to this use-case: MOB-585

What are the relevant tickets?

Tickets related to this pull-request: MOB-585

Code Review Checklist

• [ ] Architecture
• [ ] Documentation on public interfaces
• [ ] Database changed?
• [ ] If yes - Database migration?
• [ ] Remove comments & unused code & forgotten testing Logs
• [ ] Codestyle
• [ ] Functional QA tests pass