Upgrade remaining dependencies to completely get rid of aws-sdk-go

## Enhancement

Although TiDB no longer imports `aws-sdk-go` directly now, it is still being kept alive via these 3 dependencies:

1. **`github.com/ks3sdklib/aws-sdk-go` v1.2.9**. This library has removed all aws dependency since v1.3.0 (https://github.com/ks3sdklib/aws-sdk-go/commit/fbf24e171603d604d9868190969c329284b4dde6). The current version is v1.10.0
2. **`github.com/johannesboyne/gofakes3` v0.0.0-20230506070712-04da935ef877**. This library has migrated to aws-sdk-go-v2 since their 1.0.0 (but the tag is not named correctly johannesboyne/gofakes3#116 so we still have to refer it in its pseudo-version v0.0.0-20250916175020-ebf3e50324d3). This module is only used in tests.
3. **`github.com/prometheus/common/sigv4` v0.1.0**, pulled in via **`github.com/prometheus/prometheus` v0.50.1**. Prometheus has migrated to aws-sdk-go-v2 since v0.307.0. The latest version is v0.311.2. This module is only used in tests.

---

P.S. It seems the whole reason why we depend on Prometheus proper is just https://github.com/pingcap/tidb/blob/e3f45e476d364168cd324e1749dcc7eb055e088c/pkg/infoschema/metrics_schema_test.go#L66-L67 which is pretty wasteful IMO