Fixed KiotaRequestAdapterHook _is_http_client_closed method wrongly returning True when transport was not opened yet

[dabla]

Fix _is_http_client_closed incorrectly treating a never-opened transport as closed

Problem

KiotaRequestAdapterHook._is_http_client_closed contained a logic error:

# Before
if not transport._has_been_opened and transport.session is None:
    return True  # ← wrong: this means "never used", not "closed"

When the underlying Azure credential AioHttpTransport had never been opened (has_been_opened=False, session=None), the method returned True, signalling that the HTTP client was closed. As a result, get_async_conn discarded and rebuilt the cached RequestAdapter on every invocation even though it was perfectly healthy.

Fix

Return False for this branch — a transport that was never opened is not closed:

# After
if not transport._has_been_opened and transport.session is None:
    return False

This is a follow-up PR on #69128.

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Claude Opus 4.6

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