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/sled.rs

@@ -15,7 +15,9 @@ pub struct SledBlobService {
 
 impl SledBlobService {
     pub fn new(p: PathBuf) -> Result<Self, sled::Error> {
-        let config = sled::Config::default().use_compression(true).path(p);
+        let config = sled::Config::default()
+            .use_compression(false) // is a required parameter
+            .path(p);
         let db = config.open()?;
 
         Ok(Self { db })