rebase and fixup

Author: ktoso

stdlib/public/Observation/Sources/Observation/Observations.swift

@@ -236,11 +236,11 @@ public struct Observations<Element: Sendable, Failure: Error>: AsyncSequence, Se
           // back to the trailing edges of the mutations. In short, this enables the transactionality bounded by the
           // isolation of the mutation.
           await withTaskCancellationHandler(operation: {
-            await State.willChange(isolation: iterationIsolation, state: state, id: id)
+            await State.willChange(state: state, id: id)
           }, onCancel: {
             // ensure to clean out our continuation uon cancellation
             State.cancel(state, id: id)
-          }, isolation: iterationIsolation)
+          })
           return try await trackEmission(isolation: iterationIsolation, state: state, id: id)
         }
       } catch {