Agora RTC Objective-C API Reference Refactor

### - i -

- icon_height : IScreenCaptureSource::ScreenSourceListOption
- icon_width : IScreenCaptureSource::ScreenSourceListOption
- id : TConnectionInfo
- image_path : MixerLayoutConfig
- imageUrl : ImageTrackOptions , TranscodingVideoStream
- include_screen : IScreenCaptureSource::ScreenSourceListOption
- info_size : UserDataChannelInfo
- infos : UserDataChannelInfo
- injectStreamHeight : PublisherConfiguration
- injectStreamUrl : PublisherConfiguration
- injectStreamWidth : PublisherConfiguration
- input_frame_rate : LocalVideoTrackStats
- inputNumberOfChannels : AudioSessionConfiguration
- internalCodec : LocalAudioStats
- internalUid : TConnectionInfo
- interval : ContentInspectModule
- intervalInSeconds : EchoTestConfiguration
- ioBufferDuration : AudioSessionConfiguration
- ipList : LocalAccessPointConfiguration
- ipListSize : LocalAccessPointConfiguration
- is_populated_ : OptionalStorageBase< T >
- isAgoraSource : MediaSource
- isAudioFilterable : ChannelMediaOptions
- isCaptureWindow : ScreenCaptureConfiguration
- isCurrentSelected : AudioDeviceInfo
- isInteractiveAudience : ChannelMediaOptions , RtcConnectionConfiguration
- isLiveSource : MediaSource
- isLocal : VideoTrackInfo
- isLowLatencyAudioSupported : DeviceInfo
- isPlayoutDevice : AudioDeviceInfo