docs: disable bundled DB subcharts in external database guides (#3028)

Author: sebastianiv21

website/docs/getting-started/setup/instance-configuration/custom-mongodb-redis.md

@@ -78,6 +78,19 @@ Follow these steps to connect the Appsmith instance to the external MongoDB inst
       - **`{mongo.host.name}`:** The hostname or IP address of your MongoDB server. 
       - **`{db_name}`:** The name of your database within MongoDB. This is the database you want to connect to.  
 
+    For **Kubernetes (Helm)** installations, also disable the chart-managed MongoDB in `values.yaml` — the Bitnami subchart (`mongodb`) or the MongoDB Kubernetes Operator resource (`mongodbCommunity`), whichever your installation uses:
+
+    ```yaml
+    mongodb:
+      enabled: false
+
+    mongodbCommunity:
+      enabled: false
+
+    applicationConfig:
+      APPSMITH_DB_URL: "mongodb+srv://{username}:{password}@{mongo.host.name}/{db_name}"
+    ```
+
 3. Update the Appsmith server configuration to establish a connection with the external MongoDB database. This ensures that Appsmith starts using the configured MongoDB instance for all database operations.
 
    - **Docker**:

website/docs/getting-started/setup/instance-configuration/external-postgresql-rds.mdx

@@ -77,8 +77,12 @@ The `SQL_TLS_DISABLE_HOST_VERIFICATION` environment variable is only used by Tem
 2. Add or update the following environment variables with your PostgreSQL connection details:
 
     ```yaml
+    postgresql:
+      enabled: false
+
     applicationConfig:
       APPSMITH_KEYCLOAK_DB_URL: postgresql://<username>:<password>@<hostname>/<database_name>?sslmode=require
+      APPSMITH_KEYCLOAK_DB_DRIVER: postgresql
       SQL_TLS_ENABLED: true
       SQL_TLS_DISABLE_HOST_VERIFICATION: true
       SQL_TLS: true

website/docs/getting-started/setup/instance-configuration/external-redis.mdx

@@ -45,6 +45,9 @@ Follow these steps to connect your Appsmith instance to the external Redis insta
     * **Kubernetes**:
 
       ```yaml
+      redis:
+        enabled: false
+
       applicationConfig:
         APPSMITH_REDIS_URL: "redis://:{password}@{redis.instance.hostname}:{port}"
       ```