fix(pageserver): schedule compaction immediately if pending (#10684)

## Problem

The code is intended to reschedule compaction immediately if there are
pending tasks. We set the duration to 0 before if there are pending
tasks, but this will go through the `if period == Duration::ZERO {`
branch and sleep for another 10 seconds.

## Summary of changes

Set duration to 1 so that it doesn't sleep for too long.

Signed-off-by: Alex Chi Z <chi@neon.tech>

pageserver/src/tenant/tasks.rs

@@ -211,7 +211,7 @@ async fn compaction_loop(tenant: Arc<Tenant>, cancel: CancellationToken) {
                         error_run_count = 0;
                         // schedule the next compaction immediately in case there is a pending compaction task
                         sleep_duration = if let CompactionOutcome::Pending = outcome {
-                            Duration::ZERO
+                            Duration::from_secs(1)
                         } else {
                             period
                         };