186828135: Moves exception into CompletableFuture context

[julian-amplica]

This change:

• Fixes the healthcheck issue
• Moves a throw into the CompletableFuture context so we can use all the CompletableFuture methods for exception handling without any need for try-catch.
• Does not break any tests in this repo, saas-frequency-client, or custodial-wallet
• However, removing a possible throw scenario and adding a new type of exception that the CompletableFuture may resolve to has the possibility to mess up MeWe, so we may want to increment the version number accordingly and discuss this change with them

[pfrank13]

Despite it being a behavior change this seems legit from our usages, we will get this as a minor version change (or the like) and people can fork before that if needs to be but this behavior is more "correct" IMO