[Core] Rename o11y essentials tier to logs_essential (#223546)

## 📓 Summary

As a result of discussing a closer alignment between Product and
configuration naming, this change renames the observability `essentials`
tier to `logs_essentials`.

As a consequence, the specific configuration file loaded for this tier
is now named `serverless.oblt.logs_essentials.yml`.

Furthermore, this means that switching between the `complete` and
`logs_essentials` tier should now be done with

```yml
pricing.tiers.enabled: true
pricing.tiers.products:
  - name: observability
    tier: complete  # Accepted values for this tier are: complete, logs_essentials
```

.github/CODEOWNERS

@@ -1953,7 +1953,7 @@ x-pack/platform/plugins/shared/ml/server/models/data_recognizer/modules/security
 /config/serverless.es.yml @elastic/kibana-core @elastic/kibana-security @elastic/search-kibana
 /config/serverless.oblt.yml @elastic/kibana-core @elastic/kibana-security @elastic/observability-ui
 /config/serverless.oblt.complete.yml @elastic/kibana-core @elastic/observability-ui
-/config/serverless.oblt.essentials.yml @elastic/kibana-core @elastic/observability-ui
+/config/serverless.oblt.logs_essentials.yml @elastic/kibana-core @elastic/observability-ui
 /config/serverless.security.yml @elastic/kibana-core @elastic/security-solution @elastic/kibana-security
 /config/serverless.security.search_ai_lake.yml @elastic/security-solution @elastic/kibana-security
 /config/serverless.security.essentials.yml @elastic/security-solution @elastic/kibana-security

.gitignore

@@ -67,7 +67,7 @@ webpackstats.json
 !/config/serverless.chat.yml
 !/config/serverless.oblt.yml
 !/config/serverless.oblt.complete.yml
-!/config/serverless.oblt.essentials.yml
+!/config/serverless.oblt.logs_essentials.yml
 !/config/serverless.security.yml
 !/config/serverless.security.essentials.yml
 !/config/serverless.security.complete.yml

config/serverless.oblt.yml

@@ -4,7 +4,7 @@
 pricing.tiers.enabled: true
 pricing.tiers.products:
   - name: observability
-    tier: complete
+    tier: complete  # Accepted values for this tier are: complete, logs_essentials
 
 # Make sure the plugins belonging to this project type are loaded
 plugins.allowlistPluginGroups: ['platform', 'observability']

src/cli/serve/compile_config_stack.test.js

@@ -202,7 +202,7 @@ describe('pricing tiers configuration', () => {
         pricing: {
           tiers: {
             enabled: true,
-            products: [{ name: 'observability', tier: 'essentials' }],
+            products: [{ name: 'observability', tier: 'logs_essentials' }],
           },
         },
         serverless: 'oblt',
@@ -217,7 +217,7 @@ describe('pricing tiers configuration', () => {
       'serverless.yml',
       'serverless.oblt.yml',
       'kibana.yml',
-      'serverless.oblt.essentials.yml',
+      'serverless.oblt.logs_essentials.yml',
     ]);
   });
 
@@ -264,7 +264,7 @@ describe('pricing tiers configuration', () => {
         pricing: {
           tiers: {
             enabled: true,
-            products: [{ name: 'observability', tier: 'essentials' }],
+            products: [{ name: 'observability', tier: 'logs_essentials' }],
           },
         },
       },
@@ -274,7 +274,7 @@ describe('pricing tiers configuration', () => {
       'serverless.yml',
       'serverless.oblt.yml',
       'kibana.yml',
-      'serverless.oblt.essentials.yml',
+      'serverless.oblt.logs_essentials.yml',
     ]);
   });
 
@@ -316,7 +316,7 @@ describe('pricing tiers configuration', () => {
         pricing: {
           tiers: {
             enabled: false,
-            products: [{ name: 'observability', tier: 'essentials' }],
+            products: [{ name: 'observability', tier: 'logs_essentials' }],
           },
         },
         serverless: 'oblt',
@@ -358,7 +358,7 @@ describe('pricing tiers configuration', () => {
             enabled: true,
             products: [
               { name: 'observability', tier: 'complete' },
-              { name: 'observability', tier: 'essentials' },
+              { name: 'observability', tier: 'logs_essentials' },
             ],
           },
         },

src/core/packages/pricing/common/src/pricing_tiers_config.ts

@@ -18,7 +18,7 @@ import { TypeOf, offeringBasedSchema, schema } from '@kbn/config-schema';
 export const pricingProductsSchema = schema.oneOf([
   schema.object({
     name: schema.literal('observability'),
-    tier: schema.oneOf([schema.literal('complete'), schema.literal('essentials')]),
+    tier: schema.oneOf([schema.literal('complete'), schema.literal('logs_essentials')]),
   }),
   schema.object({
     name: schema.literal('ai_soc'),