cli: stop using shared id prefix context to compute immutable heads

It's unlikely that the immutable set is defined by short hashes, and more
importantly, the cache must not be initialized by using tx.repo().

cli/src/cli_util.rs

···
                 Ok(())
             };
         }
+
+        // Not using self.id_prefix_context() because the disambiguation data
+        // must not be calculated and cached against arbitrary repo. It's also
+        // unlikely that the immutable expression contains short hashes.
+        let id_prefix_context = IdPrefixContext::new(self.revset_extensions.clone());
         let to_rewrite_revset =
             RevsetExpression::commits(commits.into_iter().cloned().collect_vec());
         let immutable = revset_util::parse_immutable_expression(&self.revset_parse_context())
···
         let mut expression = RevsetExpressionEvaluator::new(
             repo,
             self.revset_extensions.clone(),
-            self.id_prefix_context()?,
+            &id_prefix_context,
             immutable,
         );
         expression.intersect_with(&to_rewrite_revset);