Update ci_job_variables.raw to FALSE

What does this MR do and why?

In previous work (!98527 (merged)), we added a migration that re-adding the ci_job_variables.raw column to make all the raw columns as FALSE because we do not set TRUE anywhere.

During this migration, we missed a place where multi-version deployments can cause wrong data.

So in this new background migration, we will fix the old data.

Explanation of the wrong data: !98527 (comment 1126894456)

Step	MR
1. Remove and add the raw attribute again	!98527 (merged)
2. Add background migration to update ci_job_variables.raw (!98527 (comment 1126894456))	<-- HERE
3. (Optional) Change the logic of to_runner_variable to support raw.	!100020 (merged)

Related to #374616 (closed)

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