Register the new Locale Variable Upgrade Task as a DataTask

[fabrizzio-dotCMS]

Parent Issue

#25603

Task

Once the Language Variables Portlet gets updated to save Lang Vars as content
We need to register the class Task240306MigrateLegacyLanguageVariables as a DataTask in the TaskLocatorUtil
So it becomes available when upgrading
The Task must be registered in the collection returned by the method getStartupRunOnceDataTaskClasses

If another UpgradeTask comes in before the portlet gets updated. The Upgrade Task Task240306MigrateLegacyLanguageVariables must be renamed to fit accordingly within the timeline.

Important note: This change must be implemented after this card

Proposed Objective

Customer Success

Proposed Priority

Priority 3 - Average

Acceptance Criteria

The task must be registered as a DataTask in TaskLocatorUtil#getStartupRunOnceDataTaskClasses.
I addition to that, a dotCMS upgrade must be executed to make sure the upgrade task is running as expected.

External Links... Slack Conversations, Support Tickets, Figma Designs, etc.

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Assumptions & Initiation Needs

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Quality Assurance Notes & Workarounds

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Sub-Tasks & Estimates

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