Fix H.265 wording in RTC 4.7.0 API reference

[Foesa-yyx]

Summary

• Link VideoEncoderConfiguration in the Android and C++ H.265 encoder descriptions.
• Replace software H.265 licensing language with the requested Agora Support guidance.

Verification

• xmllint --noout en-US/dita/RTC-AIDOC/API/api_irtcengine_setvideoencoderconfiguration.dita
• Confirmed both platform key maps resolve VideoEncoderConfiguration to class_videoencoderconfiguration.dita.
• git diff --check
• Full DITA HTML build not run: Java Runtime is unavailable locally. Please verify the generated links in the API reference preview before publishing.