fix: update Kubernetes upgrade instructions to explicitly set image tag (#2903)

## Description 

I'm updating the Kubernetes upgrade steps to explicitly set the version
that should be used.

The old method assumed that the administrator was installing Appsmith in
a non-HA installation and they actually may or may not actually trigger
an upgrade in the default situation: it depends upon whether the new pod
gets scheduled on a new node or not. It could even trigger a downgrade
if the pod got scheduled on a node that happened to have an older copy
of the Appsmith image.

I'm going to open a separate ticket to revamp the installation
instructions for Kubernetes as using `latest` can lead to some
unexpected situations depending upon how the cluster is setup.

## Pull request type

Check the appropriate box:

- [ ] Review Fixes
- [x] Documentation Overhaul
- [ ] Feature/Story
    - Link one or more Engineering Tickets
        * 
- [ ] A-Force
- [ ] Error in documentation
- [ ] Maintenance

## Documentation tickets

 Link to one or more documentation tickets:
 - 

## Checklist

From the below options, select the ones that are applicable:

- [ ] Checked for Grammarly suggestions.
- [ ] Adhered to the writing checklist.
- [ ] Adhered to the media checklist.
- [ ] Verified and updated cross-references or added redirect rules.
- [ ] Tested the redirect rules on deploy preview.
- [ ] Validated the modifications made to the content on the deploy
preview.
- [ ] Validated the CSS modifications on different screen sizes.

Author: wyattwalter

website/docs/getting-started/setup/instance-management/update-appsmith.mdx

@@ -49,15 +49,38 @@ If your current version is older than v1.9.2. Refer to the [Upgrade to Checkpoin
 If your current version is older than v1.9.2. Refer to the [Upgrade to Checkpoint Version (v1.9.2)](/getting-started/setup/instance-management/upgrade-to-checkpoint-version) guide before updating Appsmith to the latest release.  
 :::
 
-1. Restart the container image:
-   - For **Commercial Edition**:  
+> **Note**: The following instructions assume you followed our [Kubernetes install guide](https://docs.appsmith.com/getting-started/setup/installation-guides/kubernetes) exactly. If you made changes—such as using a different Helm release name, namespace, etc.—you’ll need to adjust the commands accordingly.
+
+1. Retrieve the latest Appsmith version
+   Find the latest release version on [GitHub](https://github.com/appsmithorg/appsmith/releases).
+
+2. Locate your Helm `values.yaml` file
+   - If you still have the `values.yaml` file from your initial installation, navigate to its directory:
      ```bash
-     kubectl rollout restart deployment appsmith
+     cd /path/to/your/values-file
      ```
-   - For **Community Edition**:  
+   - If you no longer have the file, you can retrieve it from your cluster:
+     ```bash
+     helm get values appsmith-ee -n appsmith-ee | grep -v "USER-SUPPLIED" > values.yaml
+     ```
+
+3. Update the image tag in `values.yaml`
+   - If you have [`yq`](https://github.com/mikefarah/yq) installed:
      ```bash
-     kubectl rollout restart statefulset appsmith
+     APPSMITH_VERSION=<version>
+     yq -i ".image.tag = \"$APPSMITH_VERSION\"" values.yaml
      ```
+   - If you don’t have `yq`, manually edit `values.yaml` with your preferred text editor to set the new version:
+     ```yaml
+     image:
+       tag: <version>
+     ```
+
+4. Apply the upgrade using Helm
+   Run the following command to upgrade your Appsmith installation:
+   ```bash
+   helm upgrade appsmith-ee -n appsmith-ee -f values.yaml
+   ```
 
 </TabItem>
 
@@ -107,4 +130,4 @@ If you encounter errors during the update, roll back to a previous version using
 
 ## See also
 
-- [Schedule automatic updates for Appsmith installation](/getting-started/setup/instance-management/maintenance-window): Learn how to schedule updates to keep your installation up-to-date effortlessly.
+- [Schedule automatic updates for Appsmith installation](/getting-started/setup/instance-management/maintenance-window): Learn how to schedule updates to keep your installation up-to-date effortlessly.