UI: Change default sample rate to 48 kHz

In a discussion on Discord the consensus was that 48 kHz is a better
default. This was prompted by the merge of the rnnoise library which can
only handle 48 kHz natively. 48 kHz is also more commonly used as a
default on personal computers.

UI/window-basic-main.cpp

@@ -1397,7 +1397,7 @@ bool OBSBasic::InitBasicConfigDefaults()
 		basicConfig, "Audio", "MonitoringDeviceName",
 		Str("Basic.Settings.Advanced.Audio.MonitoringDevice"
 		    ".Default"));
-	config_set_default_uint(basicConfig, "Audio", "SampleRate", 44100);
+	config_set_default_uint(basicConfig, "Audio", "SampleRate", 48000);
 	config_set_default_string(basicConfig, "Audio", "ChannelSetup",
 				  "Stereo");
 	config_set_default_double(basicConfig, "Audio", "MeterDecayRate",