[SPARK-52835] Fix the default value of operatorContainer memory to 2Gi from 4Gi

### What changes were proposed in this pull request?

This PR aims to fix the default value documentation of `operatorContainer` memory to `2Gi` from `4Gi`.

### Why are the changes needed?

To provide a correct information.

https://github.com/apache/spark-kubernetes-operator/blob/b504f8fb097fbafb13722c3ff36221f7fdc322c9/build-tools/helm/spark-kubernetes-operator/values.yaml#L54

### Does this PR introduce _any_ user-facing change?

No, this is only a documentation fix.

### How was this patch tested?

Manual review because this is a doc change.

### Was this patch authored or co-authored using generative AI tooling?

No.

Closes apache#288 from dongjoon-hyun/SPARK-52835.

Authored-by: Dongjoon Hyun <[email protected]>
Signed-off-by: Dongjoon Hyun <[email protected]>

Author: dongjoon-hyun

docs/operations.md

@@ -81,7 +81,7 @@ following table:
 | operatorDeployment.operatorPod.operatorContainer.envFrom         | Custom envFrom to be added to the operator container, e.g. for downward API.                                                                                                   |                                                                                                         |
 | operatorDeployment.operatorPod.operatorContainer.probes          | Probe config for the operator container.                                                                                                                                       |                                                                                                         |
 | operatorDeployment.operatorPod.operatorContainer.securityContext | Security context overrides for the operator container.                                                                                                                         | run as non root for baseline secuirty standard compliance                                               |
-| operatorDeployment.operatorPod.operatorContainer.resources       | Resources for the operator container.                                                                                                                                          | memory 4Gi, ephemeral storage 2Gi and 1 cpu                                                             |
+| operatorDeployment.operatorPod.operatorContainer.resources       | Resources for the operator container.                                                                                                                                          | memory 2Gi, ephemeral storage 2Gi and 1 cpu                                                             |
 | operatorDeployment.additionalContainers                          | Additional containers to be added to the operator pod, e.g. sidecar.                                                                                                           |                                                                                                         |
 | operatorRbac.serviceAccount.create                               | Whether to create service account for operator to use.                                                                                                                         | true                                                                                                    |
 | operatorRbac.serviceAccount.name                                 | Name of the operator Role.                                                                                                                                                     | `"spark-operator"`                                                                                      |