refactor: conform Task to Loggable instead of using a stub enum

Replace the private `DiscardingTask: Loggable` stub with a constrained
conformance `Task: Loggable where Success == Void, Failure == Never`,
and switch the helpers' logging calls to `Self.log(...)`.

Side benefit: log lines now correctly report the originating type as
`Task<Void, Never>` rather than the leaking-implementation `DiscardingTask`.

The conformance is constrained to the same Task variant the helpers
operate on, so the addition doesn't pollute the general Task type.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: pblazej

Sources/LiveKit/Support/Async/Task+Discarding.swift

@@ -16,7 +16,7 @@
 
 import Foundation
 
-private enum DiscardingTask: Loggable {}
+extension Task: Loggable where Success == Void, Failure == Never {}
 
 extension Task where Success == Void, Failure == Never {
     /// Spawn an unstructured task whose thrown errors are discarded.
@@ -40,8 +40,8 @@ extension Task where Success == Void, Failure == Never {
             do {
                 _ = try await operation()
             } catch {
-                DiscardingTask.log("Task error: \(error)", .error,
-                                   file: file, function: function, line: line)
+                Self.log("Task error: \(error)", .error,
+                         file: file, function: function, line: line)
             }
         }
     }
@@ -66,8 +66,8 @@ extension Task where Success == Void, Failure == Never {
             do {
                 _ = try await operation()
             } catch {
-                DiscardingTask.log("Task error: \(error)", .error,
-                                   file: file, function: function, line: line)
+                Self.log("Task error: \(error)", .error,
+                         file: file, function: function, line: line)
             }
         }
     }