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
NONE
```

* fix i18n

also fix unit tests

```release-note
NONE
```

* For fresh installations, default to true

```release-note
NONE
```

* gofmt files

```release-note
NONE
```

* Fixing some more strings

```release-note
NONE
```

* Update e2e tests

```release-note
NONE
```

e2e-tests/cypress/tests/integration/channels/enterprise/system_console/cluster_spec.js

@@ -17,11 +17,11 @@ describe('Cluster', () => {
         // * Check if server has license
         cy.apiRequireLicense();
 
-        // # Reset Experimental Gossip Encryption
+        // # Reset Gossip Encryption
         cy.apiUpdateConfig({
             ClusterSettings: {
                 Enable: null,
-                EnableExperimentalGossipEncryption: null,
+                EnableGossipEncryption: null,
             },
         });
 
@@ -29,31 +29,31 @@ describe('Cluster', () => {
         cy.visit('/admin_console/environment/high_availability');
     });
 
-    it('SC25050 - Can change Experimental Gossip Encryption', () => {
-        cy.findByTestId('EnableExperimentalGossipEncryption').scrollIntoView().should('be.visible').within(() => {
+    it('SC25050 - Can change Gossip Encryption', () => {
+        cy.findByTestId('EnableGossipEncryption').scrollIntoView().should('be.visible').within(() => {
             // * Verify that setting is visible and matches text content
-            cy.get('.control-label').should('be.visible').and('have.text', 'Enable Experimental Gossip encryption:');
+            cy.get('.control-label').should('be.visible').and('have.text', 'Enable Gossip encryption:');
 
             // * Verify that the help setting is visible and matches text content
             const contents = 'When true, all communication through the gossip protocol will be encrypted.';
             cy.get('.help-text').should('be.visible').and('have.text', contents);
 
-            // * Verify that Experimental Gossip Encryption is set to false by default
-            cy.get('#EnableExperimentalGossipEncryptionfalse').should('have.attr', 'checked');
+            // * Verify that Gossip Encryption is set to true by default
+            cy.get('#EnableGossipEncryptiontrue').should('have.attr', 'checked');
         });
 
-        // # Enable Experimental Gossip Encryption
+        // # Enable Gossip Encryption
         cy.apiUpdateConfig({
             ClusterSettings: {
                 Enable: true,
-                EnableExperimentalGossipEncryption: true,
+                EnableGossipEncryption: true,
             },
         });
         cy.reload();
 
-        cy.findByTestId('EnableExperimentalGossipEncryption').scrollIntoView().should('be.visible').within(() => {
-            // * Verify that Experimental Gossip Encryption is set to true
-            cy.get('#EnableExperimentalGossipEncryptiontrue').should('have.attr', 'checked');
+        cy.findByTestId('EnableGossipEncryption').scrollIntoView().should('be.visible').within(() => {
+            // * Verify that Gossip Encryption is set to true
+            cy.get('#EnableGossipEncryptiontrue').should('have.attr', 'checked');
         });
     });
 

e2e-tests/cypress/tests/support/api/on_prem_default_config.json

@@ -471,7 +471,7 @@
         "AdvertiseAddress": "",
         "UseIPAddress": true,
         "EnableGossipCompression": true,
-        "EnableExperimentalGossipEncryption": false,
+        "EnableGossipEncryption": false,
         "ReadOnlyConfig": true,
         "GossipPort": 8074
     },

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,
     },