Remove 'UserPortalDataMigrator' steps from the APIM migration document

[sanethmaduranga]

Description:
The APIM migration document[1] contains the 'Step 3' which is related to the identity components migration of the APIM server.
There we are removing a set of unwanted migration steps when the migration process is based on the APIM servers(Not the WSO2-IS servers as the key-manager).
In that, under the 'Remove the following 3 steps from migration-config.yaml, which are included under version: "5.11.0".' section, we are removing a set of migration steps.
Under the same section, we need to add the below steps as removal steps.

 - name: "UserPortalDataMigrator"
  order: 9
  parameters:
    location: "step4"
    schema: "identity"
- name: "UserPortalDataMigrator"
  order: 10
  parameters:
    location: "step4"
    schema: "um"

Suggested Labels:
migration, migration-to-4.0.0, migration-to-4.1.0, migration-to-4.2.0

Affected Product Version: APIM-4.0.0, APIM-4.1.0, APIM-4.2.0

Related Issues:
https://github.com/wso2-enterprise/wso2-apim-internal/issues/5335

References:
[1] - https://github.com/wso2-enterprise/migration-docs/blob/main/api-manager/migration-docs/apim/apim-4.2.0/apim/upgrading-from-320-to-420.md

[LayaniMal]

Hi Team,

Kind reminder on this.

Regards,
Layani