fix: restrict registration gift to parent wallets

[samwel141]

Description

Restricts the first-wallet count used by the registration gift flow to parent wallet creation. Managed wallet creation no longer runs the count or qualifies for the registration gift.

Follow-up to the review on #543.

Issue(s) addressed

• Resolves the parent-wallet guard requested in fix: restore unit test stability on feat/gift-token #543

What kind of change(s) does this PR introduce?

• Enhancement
• Bug fix
• Refactor

Please check if the PR fulfils these requirements

• The commit message follows our guidelines
• Existing unit tests pass
• Docs have been added / updated (not applicable)

Issue

What is the current behavior?
The first-wallet count runs for both parent and managed wallet creation, allowing managed wallets to enter the registration gift decision.

What is the new behavior?
The first-wallet count only runs when creating a parent wallet (!wallet_id).

Breaking change

Does this PR introduce a breaking change?
No.

Other useful information

npm run test-unit-ci: 234 passing.