Make Audio Clicky's randomness a float

Rather than a define, but read from the define.  This way, a smart coder could externally configure the randomness, changing it on the fly

This is also a precursor step to adding full on support for configurable randomness.

quantum/process_keycode/process_clicky.c

@@ -20,6 +20,7 @@
 #endif // !AUDIO_CLICKY_FREQ_RANDOMNESS
 
 float clicky_freq = AUDIO_CLICKY_FREQ_DEFAULT;
+float clicky_rand = AUDIO_CLICKY_FREQ_RANDOMNESS;
 float clicky_song[][2]  = {{AUDIO_CLICKY_FREQ_DEFAULT, 3}, {AUDIO_CLICKY_FREQ_DEFAULT, 1}}; // 3 and 1 --> durations
 
 extern audio_config_t audio_config;
@@ -33,8 +34,8 @@ void clicky_play(void) {
 #ifndef NO_MUSIC_MODE
   if (music_activated || midi_activated) return;
 #endif // !NO_MUSIC_MODE
-  clicky_song[0][0] = 2.0f * clicky_freq * (1.0f + AUDIO_CLICKY_FREQ_RANDOMNESS * ( ((float)rand()) / ((float)(RAND_MAX)) ) );
-  clicky_song[1][0] = clicky_freq * (1.0f + AUDIO_CLICKY_FREQ_RANDOMNESS * ( ((float)rand()) / ((float)(RAND_MAX)) ) );
+  clicky_song[0][0] = 2.0f * clicky_freq * (1.0f + clicky_rand * ( ((float)rand()) / ((float)(RAND_MAX)) ) );
+  clicky_song[1][0] = clicky_freq * (1.0f + clicky_rand * ( ((float)rand()) / ((float)(RAND_MAX)) ) );
   PLAY_SONG(clicky_song);
 }