ci: use LONGPATH for the windows container

ci: use LONGPATH for the windows container

Sometimes the CI might create paths that are bigger than the 260
character limit.

ex:
```
error: unable to create file subprojects/gst-integration-testsuites/testsuites/validate/h264/parse.trickmode_predicted.seek_trickmode_predicted/flow-expectations/log-parse-src-expected: Filename too long
```

https://docs.microsoft.com/en-us/windows/win32/fileio/maximum-file-path-limitation

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/2395>