Sora CPP SDK の 2024.8.0-canary.26 の変更に対応

[torikizi]

This pull request primarily focuses on updating the codebase to replace absl::optional and absl::nullopt with std::optional and std::nullopt respectively. These changes span across multiple files and functions to ensure consistency and compatibility with the updated Sora C++ SDK.

Key changes include:

SDK and Dependency Updates:

• Updated Sora C++ SDK to version 2024.8.0, which includes changes from absl::optional to std::optional and from absl::nullopt to std::nullopt.

Decoder Changes:

• Replaced absl::optional<int> with std::optional<int> in DynamicH264Decoder::Decode.
• Updated the call to callback_->Decoded to use std::nullopt instead of absl::nullopt.

Encoder Changes:

• Changed NumberOfThreads function to use std::optional<int> instead of absl::optional<int>.
• Updated ScalabilityModeFromTemporalLayers to return std::optional<ScalabilityMode> and use std::nullopt. [1] [2]
• Modified DynamicH264Encoder class to use std::optional for scalability_modes_ and encoder_thread_limit_ members.

Audio Handling Changes:

• Updated SoraAudioSinkImpl::OnData and SoraAudioSourceInterface::OnData to use std::optional<int64_t> instead of absl::optional<int64_t>. [1] [2]
• Changed SoraAudioSourceInterface::Add10MsData and SoraAudioSource::OnData to use std::optional<int64_t> and std::nullopt. [1] [2] [3]
• Modified SoraAudioStreamSinkImpl::OnData to use std::optional<int64_t> instead of absl::optional<int64_t>.

These updates ensure that the codebase is aligned with the latest standards and improves overall maintainability and compatibility.

[miosakuma]

確認しました、対応ありがとうございます。

[torikizi]

確認ありがとうございます。こちらマージします。