Remove default size profile and instance from OperandConfig template

[YCShen1010]

Issue: https://github.ibm.com/ibmprivatecloud/roadmap/issues/61284

After implementing the ODLM's capability to deep merge Kubernetes resources logic, we could remove the default size profile and instance in OperandConfig template. Therefore, we should observe a consistent change in the number of instances during common-service reconciliation, rather than fluctuating between 3, 1, and 3.

Before removing the hardcoded size and instance:

1. When deploying KeyCloak for the first time, the instance created in KeyCloak CR would be 1.
2. Then if the user configures a large size in CS CR, the instance will change to 3.
3. If it is upgraded to a new version, we will observe the instance changing back to 1, as CS applies the default value of 1 from OperandConfig during reconciliation.
4. Finally, it will ultimately change to 3, as the size is configured as large in the CS CR

After removing:

1. The instance would always remain 3 without alteration, as long as the user configures it to a large size.

[Daniel-Fan]

/lgtm

[ibm-ci-bot]

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