get All Configuration
Fetches every configuration block in one request and caches each present block under the same storage key its individual endpoint uses, turning those fetches into cache hits. An omitted block is skipped rather than cleared, so its individual getter still refreshes it and falls back to the stored value if that fails.
Concurrent callers join a single in-flight request so a launch never fans out into duplicate /config/all round-trips.
Return
The parsed ConfigurationResponses.GetAllConfigurationResponse, or null if the request fails or the response cannot be parsed.