TD-4950 Removes using DB name from scripts

TD-4950

Removes the Using statement from the migration scripts erroneously included in the previous commit.

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I have:

[x] Run the formatter and made sure there are no IDE errors (see info on Text Editor settings to avoid whitespace changes)
[ ] Written tests for the changes (accessibility tests, unit tests for controller, data services, services, view models, etc)
[x] Manually tested my work with and without JavaScript
[ ] Tested any Views or partials created or changed with Wave Chrome plugin and addressed any valid accessibility issues
[ ] Updated/added documentation in Confluence and/or GitHub Readme. List of documentation links added/changed:
- doc_1_here
[ ] Updated my Jira ticket with information about other parts of the system that were touched as part of the MR and have to be sanity tested to ensure nothing’s broken
[x] Scanned over my pull request in GitHub and addressed any warnings from the GitHub Build and Test checks.

TechnologyEnhancedLearning / DLSV2