audio: Load .WAV files with format->blockalign==0.

In theory this is illegal, but legit wavefiles in the field do it, and
it's easy to bump it to 1 for general purposes.

Formats with more specific alignment requirements already check for them
separately.

Fixes #7714.

src/audio/SDL_wave.c

@@ -1709,7 +1709,7 @@ static int WaveCheckFormat(WaveFile *file, size_t datalength)
 
         /* All supported formats must have a proper block size. */
         if (format->blockalign == 0) {
-            return SDL_SetError("Invalid block alignment");
+            format->blockalign = 1;  /* force it to 1 if it was unset. */
         }
 
         /* If the fact chunk is valid and the appropriate hint is set, the