fix: Use fromJson method instead of fromDBJson in BulkImportUser

[anku255]

Summary of change

(A few sentences about this PR)

Related issues

• Bulk User Import into SuperTokens supertokens-core#912

Test Plan

(Write your test plan here. If you changed any code, please provide us with clear instructions on how you verified your changes work. Bonus points for screenshots and videos!)

Documentation changes

(If relevant, please create a PR in our docs repo, or create a checklist here highlighting the necessary changes)

Checklist for important updates

• Changelog has been updated
• pluginInterfaceSupported.json file has been updated (if needed)
• Changes to the version if needed
  • In build.gradle
• Had installed and ran the pre-commit hook
• If there are new dependencies that have been added in build.gradle, please make sure to add them in implementationDependencies.json.
• Issue this PR against the latest non released version branch.
  • To know which one it is, run find the latest released tag (git tag) in the format vX.Y.Z, and then find the latest branch (git branch --all) whose X.Y is greater than the latest released tag.
  • If no such branch exists, then create one from the latest released branch.