Feature/add refresh obligation

[SadMouseDev]

Currently, it's impossible for users to refresh their obligations without triggering borrow/withdraw/liquidate operations. Adding a separate function within lending_market allows users to trigger obligation refreshes.

Changes made:

• Added public fun refresh_obligation<P> within the lending_market module. This follows the same coding patterns as other functions. I chose obligation_owner_cap as the argument so that only users themselves can trigger this refresh. It might also be useful to accept obligation_id instead, so that anyone could trigger this function. However, I'm using obligation_owner_cap because it doesn't open doors for potential abuse.
• In lending_market_tests.move: Added test_refresh_obligation() for the happy path and test_refresh_obligation_stale_oracle() for the unhappy path.