NE-2065: Add conflicting subscriptions section to Gateway API enhancement

[rfredette]

Amend the Gateway API enhancement to include a section on dealing with conflicting subscriptions.

[openshift-ci-robot]

@rfredette: This pull request references NE-2065 which is a valid jira issue.

Warning: The referenced jira issue has an invalid target version for the target branch this PR targets: expected the story to target the "4.20.0" version, but no target version was set.

In response to this:

Amend the Gateway API enhancement to include a section on dealing with conflicting subscriptions.

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[openshift-ci]

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[openshift-ci]

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