Reset feature-flag-called tracker on flag reload

[marandaneto]

Summary

Reset feature-flag-called dedupe tracker when flags are reloaded in the Ruby SDK.

Spec

• sdk-specs/openspec/specs/feature-flag-called-tracker/spec.md

Current evidence

The SDK audit found the dedupe map is not cleared by reload_feature_flags / flag definition reload.

Expected behavior

• Clear/reset $feature_flag_called dedupe state when feature flags/definitions are reloaded or reset.
• Ensure the next access after a reload can emit fresh tracking events.
• Preserve duplicate suppression for unchanged repeated reads between reloads.
• Add tests covering tracking before and after reload.