Add option to disable audio filters on custom playback speeds

Expected behavior of the wanted feature

Sometimes we use audio filters for simple things like normalization, like:
af=lavfi=[loudnorm=I=-16:TP=-3:LRA=10]

On certain tracks, those filters can be applied in real time at custom playback speeds without causing any issue. But there are cases, specially for multichannel audio inputs, where trying to apply those filters at faster speeds will cause multiple problems, like stutters, buffering, de-synchronization, etc.

I can't confirm if the issue is global across different platforms because I only use Windows, and I acknowledge it may be a key factor.

I use a lua script to store the current applied filters and disabling them when playback speed is changed, and restore when back to 1x. I wanted to suggest this be a standard MPV behavior, either by default or through the passing of a custom argument in the conf file.

Alternative behavior of the wanted feature

No response

Log File

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Sample Files

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No source files or tests are named. Start by locating mpv's audio-filter handling and custom playback-speed handling, then trace how configuration options are defined; done should mean a configurable way to disable filters at affected speeds and restore them at normal speed without the reported stuttering, buffering, or synchronization problems.