chore(tvix): drop sled compression support

It's been a while since the last sled release, and that one binds to a
pretty old version of zstd, requiring workarounds like cl/10090.

Upstream sled main branch currently has zstd halfway patched out (it's
a no-op, but the feature flag and options are still there), and it's in
that state for a year.

Rather than maintaining our own fork of sled, let's just stop using the
compression feature in sled, dropping the version pin to zstd that way,
removing the need for cl/10090.

This doesn't mean we won't reintroduce per-blob compression - but we
probably just won't let sled take care of the compression, but do it
ourselves - which is necessary for more chunked blob storage anyways.

Even though we do drop the feature flag, we still need to explicitly use
use_compression(false).

Change-Id: I0e4892d29e41c76653272dc1a3625180da6fee12
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10257
Autosubmit: flokli <flokli@flokli.de>
Reviewed-by: raitobezarius <tvl@lahfa.xyz>
Tested-by: BuildkiteCI

tvix/castore/src/blobservice/from_addr.rs

@@ -36,7 +36,7 @@ pub async fn from_addr(uri: &str) -> Result<Arc<dyn BlobService>, crate::Error>
             ));
         }
 
-        // TODO: expose compression and other parameters as URL parameters?
+        // TODO: expose other parameters as URL parameters?
 
         if url.path().is_empty() {
             return Ok(Arc::new(