metrics: fix DiskSpaceUsage after reopen with value sep

We weren't initializing `BlobFiles.Local.LiveSize` on open, which
should be the dominating term in disk space when values are separated.

Informs #5493

Author: RaduBerinde

recovery.go

@@ -320,5 +320,10 @@ func recoverVersion(
 			vs.metrics.Table.Live.Local.Inc(localSize)
 		}
 	}
+	for blobFile := range newVersion.BlobFiles.All() {
+		if objstorage.IsLocalBlobFile(provider, blobFile.Physical.FileNum) {
+			vs.metrics.BlobFiles.Live.Local.Inc(blobFile.Physical.Size)
+		}
+	}
 	return vs, nil
 }

testdata/metrics

@@ -2190,3 +2190,38 @@ Iter category stats:
    pebble-compaction, non-latency: {BlockBytes:0 BlockBytesInCache:0 BlockReadDuration:0s}
 ----
 ----
+
+init
+----
+
+batch
+set a 012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789
+set b 012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789
+set c 012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789
+set d 012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789
+----
+
+flush
+----
+L0.0:
+  000005:[a#10,SET-a#10,SET]
+  000007:[b#11,SET-b#11,SET]
+  000009:[c#12,SET-c#12,SET]
+  000011:[d#13,SET-d#13,SET]
+Blob files:
+  B000006 physical:{000006 size:[208 (208B)] vals:[120 (120B)]}
+  B000008 physical:{000008 size:[208 (208B)] vals:[120 (120B)]}
+  B000010 physical:{000010 size:[208 (208B)] vals:[120 (120B)]}
+  B000012 physical:{000012 size:[208 (208B)] vals:[120 (120B)]}
+
+disk-usage
+----
+7,614B
+
+init reopen
+----
+
+# The disk usage is expected to go down a bit because we remove the WALs.
+disk-usage
+----
+7,097B