refactor(ecstore): huaweicloud/tencent reuse the shared S3 constructor
Migrates the Huaweicloud and Tencent tier warm backends onto the shared
S3-compatible constructor (backlog#2040). Also makes the shared
constructor's outbound-URL validation injectable per provider
(S3CompatibleWarmBackendParams::validate_endpoint) so it can centralize
rustfs/rustfs#6764's SSRF check for the providers that don't need an
exception, while accommodating rustfs/rustfs#6773's RustFS-specific
debug-only loopback opt-in without weakening the other six providers.
Updates scripts/error-other-format-baseline.txt: the one ::other(format!)
call site moves from the two per-provider files into the new shared
call site in warm_backend.rs (net call-site count unchanged).
Refs rustfs/backlog#2042
