Backport of Explicitly enable WebSocket upgrades into release/1.14.x

[hc-github-team-consul-core]

Backport

This PR is auto-generated from #18150 to be assessed for backporting due to the inclusion of the label backport/1.14.

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The person who merged in the original PR is:
@blake
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The below text is copied from the body of the original PR.

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Description

Explicitly enable WebSocket connection upgrades in Envoy's HTTP connection manager. This is required to enable mesh applications configured with the http protocol to receive WebSocket connection upgrade requests from HTTP clients.

Links

Resolves #8283.

PR Checklist

• updated test coverage
• external facing docs updated
• appropriate backport labels added
• not a security concern

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Overview of commits

• 60cbdd5 - 642c145 - b8dd99b

[github-team-consul-core-pr-approver]

Auto approved Consul Bot automated PR