fix(node_framework): Run gas adjuster task only if necessary (#2266)

## What ❔

Adds a check that would prevent gas adjuster task from actually running
if there are no users of `GasAdjuster`.

## Why ❔

`GasAdjuster` is provided as a resource for anyone to use, but its
support task uses RPC (which has usage limits), so it doesn't make sense
to run it if nobody uses `GasAdjuster`.

## Checklist

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core/node/node_framework/src/implementations/layers/l1_gas.rs

@@ -84,7 +84,17 @@ impl Task for GasAdjusterTask {
         "gas_adjuster".into()
     }
 
-    async fn run(self: Box<Self>, stop_receiver: StopReceiver) -> anyhow::Result<()> {
+    async fn run(self: Box<Self>, mut stop_receiver: StopReceiver) -> anyhow::Result<()> {
+        // Gas adjuster layer is added to provide a resource for anyone to use, but it comes with
+        // a support task. If nobody has used the resource, we don't need to run the support task.
+        if Arc::strong_count(&self.gas_adjuster) == 1 {
+            tracing::info!(
+                "Gas adjuster is not used by any other task, not running the support task"
+            );
+            stop_receiver.0.changed().await?;
+            return Ok(());
+        }
+
         self.gas_adjuster.run(stop_receiver.0).await
     }
 }