Limit number of parallel config apply connections to 100 (#12663)

## Problem

See https://databricks.slack.com/archives/C092W8NBXC0/p1752924508578339

In case of larger number of databases and large `max_connections` we can
open too many connection for parallel apply config which may cause `Too
many open files` error.

## Summary of changes

Limit maximal number of parallel config apply connections by 100.

---------

Co-authored-by: Kosntantin Knizhnik <konstantin.knizhnik@databricks.com>

compute_tools/src/spec_apply.rs

@@ -411,7 +411,8 @@ impl ComputeNode {
             .map(|limit| match limit {
                 0..10 => limit,
                 10..30 => 10,
-                30.. => limit / 3,
+                30..300 => limit / 3,
+                300.. => 100,
             })
             // If we didn't find max_connections, default to 10 concurrent connections.
             .unwrap_or(10)