refactor(multichain-account-service): add `Bip44AccountProvider` interface

[ccharly]

Explanation

Add new interface to "forward" the top-level Account type-parameter across all provider types, thus making sure providers always use the proper type.

References

N/A

Checklist

• [ ] I've updated the test suite for new or updated code as appropriate
• [ ] I've updated documentation (JSDoc, Markdown, etc.) for new or updated code as appropriate
• [ ] I've communicated my changes to consumers by updating changelogs for packages I've changed, highlighting breaking changes as necessary
• [ ] I've prepared draft pull requests for clients and consumer packages to resolve any breaking changes