[BUG] RecursionError in `_wait_with_activity_timeout` with concurrent tasks

[Arthurdw]

When multiple concurrent asyncio tasks share a single AsyncSubstrateInterface instance and make RPC calls simultaneously, it triggers a RecursionError in the _wait_with_activity_timeout method.

Reproduction

import asyncio
from async_substrate_interface import AsyncSubstrateInterface


async def concurrent_task(substrate):
    """Simulate a task making RPC calls on a shared substrate instance."""
    for _ in range(10):
        await substrate.get_block_number(None)


async def main():
    substrate = AsyncSubstrateInterface(
        url="wss://test.finney.opentensor.ai:443",
    )

    try:
        # Run 5 concurrent tasks sharing the same substrate instance
        await asyncio.gather(
            concurrent_task(substrate),
            concurrent_task(substrate),
            concurrent_task(substrate),
            concurrent_task(substrate),
            concurrent_task(substrate),
        )
        print("✅ No error detected")
    finally:
        await substrate.close()


if __name__ == "__main__":
    asyncio.run(main())

Expected Behavior

Multiple concurrent tasks should be able to share a single AsyncSubstrateInterface instance without triggering recursion errors.

Actual Behavior

RecursionError: maximum recursion depth exceeded
  File "async_substrate_interface/async_substrate.py", line 668, in _wait_with_activity_timeout
    return await self._wait_with_activity_timeout(main_task, timeout)
  [Previous line repeated 982 more times]

Environment

• Python: 3.12.11
• async-substrate-interface: >=1.5.11