fix: drop log-and-raise on the storage-channel send failure

the HTTPException handler logged at ERROR then re-raised - raise XOR log. HTTPException
propagates unwrapped per the documented error contract, so it already carries the failure
to the caller; the error log double-reported it. drop the log, keep the raise. the
genuine swallow-path WARNING elsewhere in the file is unchanged.

Signed-off-by: disqualifier <dev@disqualifier.me>

src/dpy_cache/dpy_cache.py

@@ -138,7 +138,8 @@ class DPYCache:
             try:
                 message = await self._channel.send(content=content, files=discord_files)
             except discord.HTTPException:
-                log.error("dpy_cache: send of %d file(s) to the storage channel failed", len(group))
+                # raise XOR log: HTTPException propagates unwrapped (the documented contract),
+                # so the exception carries the failure to the caller - no error log here.
                 raise
 
             attachments = list(message.attachments)