Remove redundant check of `healthy()` in `BrotliWriterBase::Initialize()` which was needed in an earlier design of `BrotliDictionary` where `BrotliWriterBase::Reset()` was responsible for propagating a failure from preparing a dictionary.
Remove redundant check of `healthy()` in `BrotliWriterBase::Initialize()`
which was needed in an earlier design of `BrotliDictionary` where
`BrotliWriterBase::Reset()` was responsible for propagating a failure
from preparing a dictionary.

PiperOrigin-RevId: 428460699

google/riegeli,google/riegeli,google/riegeli,google/riegeli