InterpreterPoolExecutor doesn't respect "thread_name_prefix"

Bug report

Bug description:

InterpreterPoolExecutor takes a thread_name_prefix parameter, but it doesn't propagate to the underlying subinterpreter.

from concurrent.futures import ThreadPoolExecutor
try:
    from concurrent.futures.interpreter import InterpreterPoolExecutor # 3.14+
except ModuleNotFoundError:
    from interpreters_backport.concurrent.futures.interpreter import InterpreterPoolExecutor 

with ThreadPoolExecutor(thread_name_prefix="test_tpe") as tpe_executor:
    tpe_executor.submit(exec, "import threading;print(threading.current_thread().name)")  # 
    
with InterpreterPoolExecutor(thread_name_prefix="test_ipe") as ipe_executor:
    ipe_executor.submit(exec, "import threading;print(threading.current_thread().name)")

Produces

test_tpe_0
Dummy-1

CPython versions tested on:

CPython main branch

Operating systems tested on:

Windows

Start with concurrent.futures.interpreter.InterpreterPoolExecutor and compare its thread_name_prefix behavior with concurrent.futures.ThreadPoolExecutor using the reproducer in the issue. Confirm that the interpreter worker reports a name using the requested prefix, and add or update coverage for the demonstrated output.