fix: Update deprecated managed role policy

[JohnStainsby]

Attaching policies to roles with managed_policy_arns is deprecated. Updating to aws_iam_role_policy_attachement

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Checklist:

Title:

• Scope included as per conventional commits
• Ticket reference included (unless it's a quick out of ticket thing)

Description:

• Link to ticket included (unless it's a quick out of ticket thing)
• Includes tests (or an explanation for why it doesn't)
• Includes any applicable changes to the documentation in this code base
• Includes link(s) to any applicable changes to the documentation in the DBT Platform Documentation (can be to a pull request)

Tasks:

• Trigger the pull request regression tests for this branch and confirm that they are passing

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 100.00%. Comparing base (795dbae) to head (45a9e13).

✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff            @@
##              main      #305   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            1         1           
  Lines           50        50           
=========================================
  Hits            50        50           

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