Update CODEOWNERS - Extend billing ownership

[djsmith85]

Type of change

- [ ] Bug fix
- [ ] New feature development
- [ ] Tech debt (refactoring, code cleanup, dependency upgrades, etc)
- [ ] Build/deploy pipeline (DevOps)
- [X] Other

Objective

The ToolsController is mostly used for billing related functions, so it makes sense to have @bitwarden/team-billing-dev own it.

Due to the naming-scheme, this fell under ownership of @bitwarden/team-tools-dev.

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