fix: don't enter error state when request is aborted

[andrew-pledge-io]

About the changes

Prevents the SDK entering the error state when a request is aborted. An aborted request doesn't indicate that there's an error, only that a new request has superseded the previous one.

An example of the current behavior:

1. Application starts up <- starts in initializing state
2. Request for flags A
3. Context updated with userId
4. Request for flags B
5. Request for flags A cancelled <- transitions to error state
6. Request for flags B completed <- transitions to healthy state

Expected behavior:

1. Application starts up <- starts in initializing state
2. Request for flags A
3. Context updated with userId
4. Request for flags B
5. Request for flags A cancelled <- remains in initializing state
6. Request for flags B completed <- transitions to healthy state

I noticed this because in our case Sentry captures console.error messages, and we are seeing a lot of Sentry issues due to the console.error in the catch handler.

[kwasniew]

Thanks for submitting this PR. We'll be looking into this today.

[kwasniew]

@andrew-pledge-io Thanks for your contribution. I tested it locally and it works fine. Merging it now and I will followup with a unit test.