Remove MeterInterface::isEnabled() and fix meter config re-enabling (#1387)

Author: Nevay

Metrics/LateBindingMeter.php

@@ -58,9 +58,4 @@ public function createObservableUpDownCounter(string $name, ?string $unit = null
     {
         return ($this->meter ??= ($this->factory)())->createObservableUpDownCounter($name, $unit, $description, $advisory, $callbacks);
     }
-
-    public function isEnabled(): bool
-    {
-        return true;
-    }
 }

Metrics/MeterInterface.php

@@ -178,6 +178,4 @@ public function createObservableUpDownCounter(
         array|callable $advisory = [],
         callable ...$callbacks,
     ): ObservableUpDownCounterInterface;
-
-    public function isEnabled(): bool;
 }

Metrics/Noop/NoopMeter.php

@@ -56,9 +56,4 @@ public function createObservableUpDownCounter(string $name, ?string $unit = null
     {
         return new NoopObservableUpDownCounter();
     }
-
-    public function isEnabled(): bool
-    {
-        return false;
-    }
 }