fix: information disclosure bug in preconditions GET (#19810)

precondition check was being honored before, validating
if anonymous access is allowed on the metadata of an
object, leading to metadata disclosure of the following
headers.

```
Last-Modified
Etag
x-amz-version-id
Expires:
Cache-Control:
```

although the information presented is minimal in nature,
and of opaque nature. It still simply discloses that an
object by a specific name exists or not without even having
enough permissions.

docs/debugging/build.sh

@@ -2,5 +2,6 @@
 
 export CGO_ENABLED=0
 for dir in docs/debugging/*/; do
-	go build -C ${dir} -v
+	bin=$(basename ${dir})
+	go build -C ${dir} -o ${PWD}/${bin}
 done