MM-63652: Transition gossip encryption functionality to GA (#33349) (#33429)

Create a new config setting, and migrate the old values to new.

https://mattermost.atlassian.net/browse/MM-63652

Skip-Enterprise-PR: true

```release-note
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* fix i18n

also fix unit tests

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* For fresh installations, default to true

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* gofmt files

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* Fixing some more strings

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* Update e2e tests

```release-note
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e2e-tests/playwright/lib/src/server/default_config.ts

@@ -587,7 +587,7 @@ const defaultServerConfig: AdminConfig = {
         AdvertiseAddress: '',
         UseIPAddress: true,
         EnableGossipCompression: true,
-        EnableExperimentalGossipEncryption: false,
+        EnableGossipEncryption: false,
         ReadOnlyConfig: true,
         GossipPort: 8074,
     },