[UII] Replace kibanaVersionCheckEnabled default value instead of config setting (#198172)

## Summary

This PR removes
`xpack.fleet.internal.registry.kibanaVersionCheckEnabled: false` from
`kibana.yml` in favor of changing the default value that Fleet
populates, so that we do not apply the Kibana version constraint to EPR
requests for >= 9.0 deployments.

Prior to this change, this setting was not applied to ESS deployments as
`kibana.yml` is overridden there.

I updated the related task in
https://github.com/elastic/kibana/issues/192624 to reflect this change.

config/kibana.yml

@@ -181,8 +181,3 @@
 # Maximum number of documents loaded by each shard to generate autocomplete suggestions.
 # This value must be a whole number greater than zero. Defaults to 100_000
 #unifiedSearch.autocomplete.valueSuggestions.terminateAfter: 100000
-
-# Must be removed before v9 release
-# Requires all registry packages to add v9 as a compatible semver range
-# https://github.com/elastic/kibana/issues/192624
-xpack.fleet.internal.registry.kibanaVersionCheckEnabled: false

x-pack/plugins/fleet/server/config.ts

@@ -201,8 +201,7 @@ export const config: PluginConfigDescriptor = {
         defaultValue: () => [],
       }),
 
-      internal: schema.maybe(
-        schema.object({
+      internal: schema.object({
         disableILMPolicies: schema.boolean({
           defaultValue: false,
         }),
@@ -220,7 +219,10 @@ export const config: PluginConfigDescriptor = {
         retrySetupOnBoot: schema.boolean({ defaultValue: false }),
         registry: schema.object(
           {
-              kibanaVersionCheckEnabled: schema.boolean({ defaultValue: true }),
+            // Must be set back to `true`  before v9 release
+            // Requires all registry packages to add v9 as a compatible semver range
+            // https://github.com/elastic/kibana/issues/192624
+            kibanaVersionCheckEnabled: schema.boolean({ defaultValue: false }),
             excludePackages: schema.arrayOf(schema.string(), { defaultValue: [] }),
             spec: schema.object(
               {
@@ -248,7 +250,10 @@ export const config: PluginConfigDescriptor = {
           },
           {
             defaultValue: {
-                kibanaVersionCheckEnabled: true,
+              // Must be set back to `true`  before v9 release
+              // Requires all registry packages to add v9 as a compatible semver range
+              // https://github.com/elastic/kibana/issues/192624
+              kibanaVersionCheckEnabled: false,
               capabilities: [],
               excludePackages: [],
               spec: {
@@ -257,8 +262,7 @@ export const config: PluginConfigDescriptor = {
             },
           }
         ),
-        })
-      ),
+      }),
       enabled: schema.boolean({ defaultValue: true }),
       /**
        * The max size of the artifacts encoded_size sum in a batch when more than one (there is at least one artifact in a batch).