Fix: Solid query `useIsMutating` throwing an error and `useMutationState` infinite loop

[dev-rb]

• Fixes an infinite loop in useMutationState caused by reading and writing to results in an effect.
• Fixes useIsMutating throwing a reading properties of undefined error caused by reading isMutating of client which could be undefined in the case of some SSR environments/setups. This fix also makes it consistent with useMutationState where the subscription is created inside of an effect

Summary by CodeRabbit

• Bug Fixes

  • More reliable mutation status updates that react correctly to changing inputs.
  • Proper cleanup of subscriptions on component unmount or re-run, reducing potential leaks.
  • Prevented stale data by resubscribing when relevant reactive sources change.

• Performance

  • Reduced unnecessary recalculations and renders by avoiding tracked reads during comparisons.
  • More efficient equality checks to minimize redundant updates.

• Refactor

  • Improved reactivity management without altering the public API.