Fix EINTR not handled in LineRequest.WaitEdgeEventsRespectfully

[karen-meyerzuhartlage-AP]

Fixes #2598

Related to #1210

LineRequest.WaitEdgeEventsRespectfully (used by LibGpiodV2Driver) calls Interop.epoll_wait without handling EINTR (errno 4). If the call is interrupted by a signal — which happens when a device resumes from standby/suspend — the method throws a GpiodException instead of retrying.

The V1 LibGpiodDriverEventHandler already ignores Interrupted system call error and continues waiting for events (see #1210). This PR implements the same behaviour for LibGpiodV2Driver.

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[karen-meyerzuhartlage-AP]

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[raffaeler]

[Triage] Code looks ok, but we require a hardware test before approving. This may take some time.

[Copilot]

Pull request overview

This PR fixes a reliability issue in the libgpiod v2 GPIO edge-event waiting path by retrying epoll_wait when it fails with EINTR, matching the existing behavior in the libgpiod v1 event handler and preventing edge-event processing from stopping after suspend/resume.

Changes:

• Add an EINTR retry loop around Interop.epoll_wait in LineRequest.WaitEdgeEventsRespectfully.
• Introduce an ERROR_CODE_EINTR constant in the v2 LineRequest proxy to align with existing drivers’ interrupt-handling patterns.

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