Suppress unnecessary warns for Windows tag group

[hsbt]

Randomized with seed 60040
./spec/realworld/edgecases_spec.rb is not assigned to any Windows runner group. see spec/support/windows_tag_group.rb for details.
./spec/realworld/git_spec.rb is not assigned to any Windows runner group. see spec/support/windows_tag_group.rb for details.
./spec/realworld/slow_perf_spec.rb is not assigned to any Windows runner group. see spec/support/windows_tag_group.rb for details.
./spec/realworld/double_check_spec.rb is not assigned to any Windows runner group. see spec/support/windows_tag_group.rb for details.
./spec/realworld/ffi_spec.rb is not assigned to any Windows runner group. see spec/support/windows_tag_group.rb for details.
./spec/realworld/parallel_spec.rb is not assigned to any Windows runner group. see spec/support/windows_tag_group.rb for details.
............

realworld examples are unnecessary for parallel tests with Windows.

[Copilot]

Pull request overview

This PR updates Bundler’s RSpec configuration to avoid emitting Windows runner-group assignment warnings for realworld specs, which are not intended to be part of the Windows parallel runner grouping.

Changes:

• Skip the “not assigned to any Windows runner group” warning for example groups tagged realworld: true.

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