(ios) crash fix: conditionally set AVAudioSession category on load

[dpa99c]

Analysis

In the current plugin implementation for iOS, if another plugin or library uses the shared AVAudioSession instance, it can conflict with this plugin, leading to an app crash with an error such as this:

ATAudioSessionPropertyManager.mm:363   FAILED to set property 1684431725 on AVAudioSession with error Error Domain=NSOSStatusErrorDomain Code=-50 "(null)"
           AURemoteIO.cpp:1666  AUIOClient_StartIO failed (561145187)
           AVAEInternal.h:104   [AVAudioEngineGraph.mm:1549:Start: (err = PerformCommand(*ioNode, kAUStartIO, NULL, 0)): error 561145187

In my case, this happened when updating to Capacitor v7, which changes how plugins are initialized at startup, and they now load earlier.
This caused a race condition between the load() function of this plugin and the initialization of another native audio library I'm using.

The other library is for audio conversations, so requires the playAndRecord AVAudioSession category to be set.
However, currently this plugin immediately sets the playback category on loading.

In the race condition, the other library sets an initial category of "playbackAndRecord", then this plugin's load() function runs and sets the category to "playback", so when the other library tries to initialize an audio session with record/playback functionality, the category is wrong, causing the app to crash.

Solution

My solution is to change the load() function of this plugin to check the current session category and only set it to "playback" if it's currently set to "record", which is the only category where playback will not work.
Any other category (e.g. playbackAndRecord) will allow playback.

This prevents any issues if another native class has set a different audio session category prior to this plugin initializing.